Antimicrobial Peptidomimetics

ABSTRACT

The present invention relates to peptidomimetics of the formula (I) or (I)c wherein L 1 , L 2 , L 3 , R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , n, m, Q, X, Z 1  and Z 2  are defined as mentioned in the description and to salts and solvates of each of these compounds and to processes for the preparation thereof, compositions containing them and the uses of such compounds. It has been found that the compounds have a high microbicide activity and are suited to combat resistant bacteria, such as meticillin-resistant  Staphylococcus aureus  (MRSA) strains, at very low concentrations.

TECHNICAL FIELD

The present invention relates to compounds, compositions, and methodsfor treating diseases and conditions. In particular, the inventionrelates to compounds, compositions, and methods for treating bacterialinfections, disorders and conditions. The invention further relates to acompound of the formula (I)

wherein

-   L₁ represents —CO—, alkandiyl, -alkyl-CO— or —CO-alkyl-;-   L₂ represents —CO—, alkandiyl, -alkyl-CO— or —CO-alkyl-;-   L₃ represents —CO—, alkandiyl, -alkyl-CO— or —CO-alkyl-;-   R₁ represents hydrogen, acyl, carbamoyl, alkylaminocarbonyl,    dialkylaminocarbonyl, arylcarbonyl, cycloalkylarbonyl or    heterocyclylcarbonyl;-   R₂ represents optionally substituted alkyl, aralkyl or    heteroaralkyl;-   R₃ represents hydrogen, or represents optionally substituted alkyl,    aralkyl or heteroaralkyl;-   R₄ represents optionally substituted alkandiyl, alkendiyl,    alkyndiyl, cycloalkyldiyl, alkylcycloalkyldiyl,    alkylcycloalkylalkyldiyl, aryldiyl, alkylaryldiyl,    alkylarylalkyldiyl;-   R₅ represents hydrogen, or represents optionally substituted alkyl,    aralkyl or heteroaralkyl;-   R₆ represents hydrogen, or represents optionally substituted alkyl,    aralkyl or heteroaralkyl;-   provided that at least two of the substituents R₂, R₃, R₅ and R₆ are    optionally substituted aralkyl or heteroaralkyl;-   n is 0, 1, 2, 3 or 4; and-   m is 0 or 1;-   Q is —NH₂, —NH—C(NH)—NH₂ or —NH—C(N-alkyl)-NH-alkyl;-   X is NH, O or S;-   Z₁ is —CH₂—;-   Z₂ is a direct bond, alkandiyl, cycloalkyldiyl or aryldiyl;    and to salts and solvates of each of these compounds and to    processes for the preparation of, compositions containing and the    uses of such compounds.

The invention also relates to their analogues of formula (Ic)

BACKGROUND

In 2011, there were 80,000 cases of invasive meticillin-resistantStaphylococcus aureus (MRSA) infections in the United States, resultingin 11,000 fatalities (Chan et al. Chemical Biology and Drug Design.2013, 82, 418-428). The emergence of multi-drug-resistant bacteria andthe lack of new antibiotics in the drug development pipelines ofpharmaceutical companies is a major health concern (Butler et al.,Journal of Antibiotics. 2011, 37, 413-425). Since 2000, only fourantibiotics with new chemical scaffolds were launched; the (i)oxazolidinone Linezolid (2000), (ii) lipopeptide Daptomycin (2003),(iii) pleuromutilin Retapamulin (2007) and (iv) macrocycle Fidaxomicin(2011) (Wright., Chemistry & Biology. 2012, 19, 3-10). Hence, there isan urgent need to develop new classes of antibacterials, especiallythose against emerging multi-drug-resistant bacteria (Projan. DrugDiscovery Today. 2008, 13, 279-280.; Cooper and Shlaes. Nature. 2011,472, 32).

SUMMARY

Novel compounds have now been found with potent bactericidal activitieswith an unknown mechanism of action.

Advantageously, according to the present invention there is provided acompound of formula (I):

wherein

-   L₁ represents —CO—, alkandiyl, -alkyl-CO— or —CO-alkyl-;-   L₂ represents —CO—, alkandiyl, -alkyl-CO— or —CO-alkyl-;-   L₃ represents —CO—, alkandiyl, -alkyl-CO— or —CO-alkyl-;-   R₁ represents hydrogen, acyl, carbamoyl, alkylaminocarbonyl,    dialkylaminocarbonyl, arylcarbonyl, cycloalkylarbonyl or    heterocyclylcarbonyl;-   R₂ represents optionally substituted alkyl, aralkyl or    heteroaralkyl;-   R₃ represents hydrogen, or represents optionally substituted alkyl,    aralkyl or heteroaralkyl;-   R₄ represents optionally substituted alkandiyl, alkendiyl,    alkyndiyl, cycloalkyldiyl, alkylcycloalkyl, alkylcycloalkylalkyl,    aryl, alkylaryl, alkylarylalkyl;-   R₅ represents hydrogen, or represents optionally substituted alkyl,    aralkyl or heteroaralkyl;-   R₆ represents hydrogen, or represents optionally substituted alkyl,    aralkyl or heteroaralkyl;-   provided that at least two of the substituents R₂, R₃, R₅ and R₆ are    aralkyl or heteroaralkyl;-   n is 0, 1, 2, 3 or 4; and-   m is 0 or 1;-   Q is —NH₂, —NH—C(NH)—NH₂ or —NH—C(N-alkyl)-NH-alkyl;-   X is NH, O or S;-   Z₁ is —CH₂—;-   Z₂ is a direct bond, alkandiyl, cycloalkyldiyl or aryldiyl;    and to salts and solvates of each of these compounds and to    processes for the preparation of, compositions containing and the    uses of such compounds.

There is also provided a compound of the formula (Ic)

wherein

-   L₁, L₂, L₃, R₁, R₂, R₃, R₄, R₅, R₆, n, m, Q, X, Z₁ and Z₂ are    defined as in formula (I), provided that at least two of the    substituents R₂, R₃, R₅ and R₆ are optionally substituted aralkyl or    heteroaralkyl, and to salts and solvates of each of these compounds,    compositions containing the compounds and the uses of such    compounds.

In the following it is mentioned how the compounds of formula (I) can beobtained.

Compounds of the formula (I′)

in which R′₁ to R′₄, m′ and n′ have the following meaning:

-   R′₁ represents hydrogen, acyl, carbamoyl, alkylaminocarbonyl,    dialkylaminocarbonyl, arylcarbonyl, cycloalkylarbonyl or    heterocyclylcarbonyl;-   R′₂ represents optionally substituted alkyl, aralkyl or    heteroaralkyl;-   R′₃ represents optionally substituted alkyl, aralkyl or    heteroaralkyl;-   R′₄ represents optionally substituted alkandiyl, alkendiyl,    alkyndiyl, cycloalkyldiyl, alkylcycloalkyl, alkylcycloalkylalkyl or    alkylaryl;-   n′ is 0, 1, 2, 3 or 4; and-   m′ is 0 or 1;-   are obtained when compounds of the formula (II′)

in which R′₃, R′₄, m and n have the meaning given above

-   are reacted in the presence of an amide/peptide coupling reagent    with compounds of the formula (III′)

wherein R′₁ and R′₂ are defined as mentioned above,

-   and deprotection with an acid.

Compounds of the formula (II′) are obtained by reacting compounds of theformula (IV′)

wherein R′₃, R′₄ and m′ are defined as mentioned above are reacted witha compound of the formula (V′)

which can exist in two forms:

wherein n′ is defined as mentioned above in the presence of a anamide/peptide coupling reagent.

Compounds of the formula (IV′) are obtained when compounds of theformula (VI′)

wherein R′₄ and m′ are defined as mentioned above,

-   are reacted in the presence of an amide/peptide coupling reagent    with compounds of the formula (VII′)

wherein R′₃ is defined as mentioned above.

Compounds of the formula (VI′) are obtained when a diamine of theformula (VIII′)

wherein R′₄ is defined as mentioned above and m′ is 1 is reacted withN,N′-di-Boc-S-methylisothiourea.

-   R′₁, R′₂, R′₃, R′₄, n′ and m′ have the preferred meaning as    mentioned for R₁, R₂, R₃, R₄, n and m.

Compounds of the formula (VI′) wherein m′ is 0 can be obtained as knownfrom the chemical literature.

The other compounds according to formula (I) and (Ic) can be madeanalogously, as mentioned in the examples or according to methods knownfrom the literature in view of the examples.

Advantageously, according to the present invention there is alsoprovided a compound of formula (Ia) which is a selected compound of theformula (I):

wherein

-   R¹ represents hydrogen, acyl, carbamoyl, alkylaminocarbonyl or    dialkylaminocarbonyl;-   R2 represents optionally substituted alkyl, aralkyl or    heteroaralkyl;-   R³ represents optionally substituted alkyl, aralkyl or    heteroaralkyl;-   R⁴ represents optionally substituted alkandiyl, alkendiyl,    alkyndiyl, cycloalkyldiyl, alkylcycloalkyl, alkylcycloalkylalkyl or    alkylaryl;-   n is 0, 1, 2, 3 or 4; and-   m is 0 or 1;-   and to pharmaceutically acceptable salts and solvates of each of    these compounds, compositions containing the compounds and the uses    of such compounds.

It has been found that the compounds of formula (Ia) are obtained by thefollowing process:

Compounds of the formula (Ia)

in which R¹ to R⁴, m and n have the meaning as in formula (Ia) areobtained when compounds of the formula (IIa)

in which R³, R⁴, m and n have the meaning in formula (Ia) are reacted inthe presence of an amide/peptide coupling reagent with compounds of theformula (IIIa)

wherein R¹ and R² are defined as in formula (Ia),

-   and deprotection with an acid.

Compounds of the formula (IIa) are obtained by reacting compounds of theformula (IVa)

wherein R³, R⁴ and m are defined as in formula (Ia) are reacted with acompound of the formula (Va)

wherein n is defined as in formula (Ia) in the presence of a anamide/peptide coupling reagent.

Compounds of the formula (IVa) are obtained when compounds of theformula (VIa)

wherein R⁴ and m are defined as in formula (Ia) above,

-   are reacted in the presence of an amide/peptide coupling reagent    with compounds of the formula (VIIa)

wherein R³ is defined as in formula (Ia).

Compounds of the formula (VIa) are obtained when a diamine of theformula (VIIIa)

wherein R⁴ is defined as in formula (Ia) above and m is 1 is reactedwith N,N′-di-Boc-S-methylisothiourea.

According to a third aspect of the invention it has been found that thenovel compounds of Formula (I) or (Ic) according to the invention arevery effective as antibacterials, advantageously also showing potentbactericidal activities against MRSA. The invention provides a method oftreating a disease, disorder or condition, wherein the disease, disorderor condition is a bacterial infection, such as for instance a skininfection (e.g. boils), a respiratory disease (e.g. sinusitis,pneumonia), food poisoning or any other life-threatening systemicdisease, in a subject in need of such treatment, comprisingadministering to said subject a compound of the formula (I) or (Ic) orpharmaceutically acceptable salts and solvates thereof.

In a fourth aspect of the invention, the present invention is directedto the use of a compound of formula (I) or (Ic) or pharmaceuticallyacceptable salts or solvates thereof in the manufacture of a medicamentfor the treatment of a disease, disorder or condition selected from anybacterial infection, such as for instance a skin infection (e.g. boils),a respiratory disease (e.g. sinusitis, pneumonia), food poisoning or anyother life-threatening systemic disease.

In a fifth aspect of the invention, the invention is directed to the useof a compound of formula (I) or (Ic) or pharmaceutically acceptablesalts and solvates thereof for use in treating a bacterial infection.

The invention is directed in another aspect to the use of a compound offormula (I) or (Ic) or pharmaceutically acceptable salts and solvatesthereof in the manufacture of a medicament for the treatment of abacterially caused disease, disorder or condition.

Another aspect of the invention is directed to a pharmaceuticalcomposition comprising a compound of formula (I) or (Ic) orpharmaceutically acceptable salts and solvates thereof, and apharmaceutically acceptable excipient.

Other and further aspects will occur to those skilled in the art inlight of this disclosure.

Definitions

The following are some definitions that may be helpful in understandingthe description of the present invention. These are intended as generaldefinitions and should in no way limit the scope of the presentinvention to those terms alone, but are put forth for a betterunderstanding of the following description.

Unless the context requires otherwise or specifically stated to thecontrary, integers, steps, or elements of the invention recited hereinas singular integers, steps or elements clearly encompass both singularand plural forms of the recited integers, steps or elements.

Throughout this specification, unless the context requires otherwise,the word “comprise”, or variations such as “comprises” or “comprising”,will be understood to imply the inclusion of a stated step or element orinteger or group of steps or elements or integers, but not the exclusionof any other step or element or integer or group of elements orintegers. Thus, in the context of this specification, the term“comprising” means “including principally, but not necessarily solely”.

Those skilled in the art will appreciate that the invention describedherein is susceptible to variations and modifications other than thosespecifically described. It is to be understood that the inventionincludes all such variations and modifications. The invention alsoincludes all of the steps, features, compositions and compounds referredto or indicated in this specification, individually or collectively, andany and all combinations or any two or more of said steps or features.As used herein, the term “alkyl group” includes within its meaningmonovalent (“alkyl”) and divalent (“alkylene”) straight chain orbranched chain saturated aliphatic groups having from 1 to 10 carbonatoms, eg, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. For example,the term alkyl includes, but is not limited to, methyl, ethyl, 1-propyl,isopropyl, 1-butyl, 2-butyl, isobutyl, tert-butyl, amyl,1,2-dimethylpropyl, 1,1-dimethylpropyl, pentyl, isopentyl, hexyl,4-methylpentyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl,2,2-dimethylbutyl, 3,3-dimethylbutyl, 1,2-dimethylbutyl,1,3-dimethylbutyl, 1,2,2-trimethylpropyl, 1,1,2-trimethylpropyl,2-ethylpentyl, 3-ethylpentyl, heptyl, 1-methylhexyl, 2,2-dimethylpentyl,3,3-dimethylpentyl, 4,4-dimethylpentyl, 1,2-dimethylpentyl,1,3-dimethylpentyl, 1,4-dimethylpentyl, 1,2,3-trimethylbutyl,1,1,2-trimethylbutyl, 1,1,3-trimethylbutyl, 5-methylheptyl,1-methylheptyl, octyl, nonyl, decyl, and the like.

The term “alkenyl group” includes within its meaning monovalent(“alkenyl”) and divalent (“alkenylene”) straight or branched chainunsaturated aliphatic hydrocarbon groups having from 2 to 10 carbonatoms, e.g., 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms and having atleast one double bond, of either E, Z, cis or trans stereochemistrywhere applicable, anywhere in the alkyl chain. Examples of alkenylgroups include but are not limited to ethenyl, vinyl, allyl,1-methylvinyl, 1-propenyl, 2-propenyl, 2-methyl-1-propenyl,2-methyl-1-propenyl, 1-butenyl, 2-butenyl, 3-butentyl, 1,3-butadienyl,1-pentenyl, 2-pententyl, 3-pentenyl, 4-pentenyl, 1,3-pentadienyl,2,4-pentadienyl, 1,4-pentadienyl, 3-methyl-2-butenyl, 1-hexenyl,2-hexenyl, 3-hexenyl, 1,3-hexadienyl, 1,4-hexadienyl, 2-methylpentenyl,1-heptenyl, 2-heptentyl, 3-heptenyl, 1-octenyl, 1-nonenyl, 1-decenyl,and the like.

The term “alkynyl group” as used herein includes within its meaningmonovalent (“alkynyl”) and divalent (“alkynylene”) straight or branchedchain unsaturated aliphatic hydrocarbon groups having from 2 to 10carbon atoms and having at least one triple bond anywhere in the carbonchain. Examples of alkynyl groups include but are not limited toethynyl, 1-propynyl, 1-butynyl, 2-butynyl, 1-methyl-2-butynyl,3-methyl-1-butynyl, 1-pentynyl, 1-hexynyl, methylpentynyl, 1-heptynyl,2-heptynyl, 1-octynyl, 2-octynyl, 1-nonyl, 1-decynyl, and the like.

The term “cycloalkyl” as used herein refers to cyclic saturatedaliphatic groups and includes within its meaning monovalent(“cycloalkyl”), and divalent (“cycloalkylene”), saturated, monocyclic,bicyclic, polycyclic or fused polycyclic hydrocarbon radicals havingfrom 3 to 10 carbon atoms, e.g., 3, 4, 5, 6, 7, 8, 9, or 10 carbonatoms. Examples of cycloalkyl groups include but are not limited tocyclopropyl, 2-methylcyclopropyl, cyclobutyl, cyclopentyl,2-methylcyclopentyl, 3-methylcyclopentyl, cyclohexyl, and the like.

The term “aryl” as used herein refers to monovalent (“aryl”) anddivalent (“arylene”) single, polynuclear, conjugated and fused residuesof aromatic hydrocarbons having from 6 to 10 carbon atoms. Examples ofsuch groups include phenyl, biphenyl, naphthyl, phenanthrenyl, and thelike.

The term “acyl” is intended to mean a —C(O)—R radical, wherein R is anoptionally substituted C₁-C₂₀-alkyl, C₂-C₂₀-alkenyl, cycloalkyl having 3to 7 carbon atoms, or aryl having or 10 carbon atoms, or a 5 to 6 ringmembered heterocycloalkyl or heteroaryl group having 1 to 3 hetero atomsselect from N, S, or O.

The term “heteroaromatic group” and variants such as “heteroaryl” or“heteroarylene” as used herein, includes within its meaning monovalent(“heteroaryl”) and divalent (“heteroarylene”), single, polynuclear,conjugated and fused aromatic radicals having 6 to 20 atoms wherein 1 to6 atoms are heteroatoms selected from O, N, NH and S. Examples of suchgroups include pyridyl, 2,2′-bipyridyl, phenanthrolinyl, quinolinyl,thiophenyl, and the like.

The term “halogen” or variants such as “halide” or “halo” as used hereinrefers to fluorine, chlorine, bromine and iodine.

The term “heteroatom” or variants such as “hetero-” as used hereinrefers to O, N, NH and S.

The term “aralkyl” as used herein, includes within its meaning (“aryl”)and divalent (“arylene”), single, polynuclear, conjugated and fusedaromatic hydrocarbon radicals attached to divalent, saturated, straightand branched chain C₁-C₆-alkylene radicals.

The term “heteroaralkyl” as used herein, includes within its meaningmonovalent (“heteroaryl”) and divalent (“heteroarylene”), single,polynuclear, conjugated and fused aromatic hydrocarbon radicals attachedto divalent saturated, straight and branched chain C₁-C₆-alkyleneradicals.

Preferably the aryl or arylene in the aralkyl has 6 or 10 carbon atoms.Preferably the heteroaryl or heteroarylene in the heteroaralkyl forms afive or six membered ring having 1 to 3 hetero atoms selected from N, Sor O. The term “optionally substituted” as used herein means the groupto which this term refers may be unsubstituted, or may be substitutedwith one or more groups independently selected from C₁-C₆-alkyl,C₂-C₆-alkenyl, C₂-C₆-alkynyl, thio-C₁-C₆-alkyl, C₃-C₈-cycloalkyl,C₃-C₈-cycloalkenyl, five to six membered heterocycloalkyl, halo, —COOH,—CONH₂, C₁-C₆-carboxyl, halo-C₁-C₆-alkyl, halo-C₂-C₆-alkynyl, hydroxyl,C₁-C₆-alkoxy, thio-C₁-C₆-alkoxy, C₂-C₆-alkenyloxy, halo-C₁-C₆-alkoxy,halo-C₂-C₆-alkenyloxy, nitro, amino, nitro-C₁-C₆-alkyl,nitro-C₂-C₆-alkenyl, nitro-C₂-C₆-alkynyl, five to six ring memberednitro-heterocyclyl, C₁-C₆-alkylamino, di-C₁-C₆-alkylamino,C₂-C₆-alkenylamine, C₂-C₆-alkynylamino, C₁-C₆-acyl, C₂-C₆-alkenoyl,C₂-C₆-alkynoyl, C₁-C₆-acylamino, di-C₁-C₆-acylamino, C₁-C₆-acyloxy,C₁-C₆-alkylsulfonyloxy, five to six ring membered heterocycloxy, five tosix ring membered heterocycloamino, five to six ring memberedhaloheterocycloalkyl, C₁-C₆-alkylsulfenyl, C₁-C₆-alkylcarbonyloxy,C₁-C₆-alkylthio, C₁-C₆-acylthio, phosphorus-containing groups such asphosphono and phosphinyl, aryl having 6 to 10 carbon atoms, five to sixring membered heteroaryl, C₁-C₄-alkylaryl having 6 or 10 carbon atoms inthe aryl, five to six ring membered C₁-C₆-alkylheteroaryl, cyano,cyanate, isocyanate, —C(O)NH(C₁-C₆-alkyl), and —C(O)N(C₁-C₆-alkyl)₂. Ifthe term “optionally substituted” is used it refers to all substituentslisted after this term, e.g. “optionally substituted methyl or ethyl”means “optionally substituted methyl” or optionally substituted ethyl”.

The present invention includes within its scope all isomeric forms ofthe compounds disclosed herein, including all diastereomeric isomers,racemates and enantiomers, unless the stereochemistry is fixed in theformula drawing. Thus, formula (I) or (Ic) should be understood toinclude, for example, E, Z, cis, trans, (R), (S), (L), (D), (+), and/or(−) forms of the compounds, as appropriate in each case, unless thestereochemistry is fixed in the formula drawing.

The term “Fmoc” or “fmoc” in the formulas and description refers to atypical fluorenylmethyloxycarbonyl protecting group.

The term “t-Boc” or “Boc” in the formulas and description refers to atypical t-butoxycarbonyl protecting group.

The term “Pbf” stands for a2,2,4,6,7-pentamethyldihydrobenzofuran-5-sulfonyl protecting group.

The term “a compound of formula (I) or (Ic) or salts or solvatesthereof” or “a compound of formula(I) or a pharmaceutically acceptablesalt or solvate thereof” is intended to identify a compound selectedfrom the group consisting of: a compound of the formula (I) or (Ic), asalt of a compound of formula(I) or (Ic), a pharmaceutically acceptablesolvate of a compound of formula (I) or (Ic) or a pharmaceuticallyacceptable solvate of a pharmaceutically acceptable salt of a compoundof formula(I) or (Ic).

The term “therapeutically effective” is intended to qualify the amountof compound or pharmaceutical composition, or the combined amount ofactive ingredients in the case of combination therapy.

The term “treatment” as used herein to describe the present inventionund unless otherwise qualified, means administration of the compound,pharmaceutical composition or combination to effect preventive,palliative, supportive, restorative or curative treatment.

The term “preventive treatment” as used herein to describe the presentinvention, means that the compound, pharmaceutical composition orcombination is administered to a subject or member of a population thatis significantly predisposed to the relevant condition.

The term “palliative treatment” as used herein to describe the presentinvention, means that the compound, pharmaceutical composition orcombination is administered to a subject to remedy signs and/or symptomsof a condition, without necessarily modifying the progression of, orunderlying etiology of, the relevant condition. Non-limiting examplesinclude reduction of pain, discomfort, swelling or fever.

The term “supportive treatment” as used herein to describe the presentinvention, means that the compound, pharmaceutical composition orcombination is administered to a subject as part of a regimen oftherapy, but that such therapy is not limited to administration of thecompound, pharmaceutical composition or combination.

The term “restorative treatment” as used herein to describe the presentinvention, means that the compound, pharmaceutical composition orcombination is administered to a subject to modify the underlyingprogression or etiology of a condition.

The term “preventive treatment” as used herein to describe the presentinvention, means that the compound, pharmaceutical composition orcombination is administered to a subject for the purpose of bringing thedisease or disorder into complete remission, or that the disorder isundetectable after such treatment.

The term “MIC” as used herein, means the minimum inhibitoryconcentration (MIC) is the lowest concentration of an antimicrobial thatwill inhibit the visible growth of a microorganism after overnightincubation.

The term “compounds of the invention” or “a compound of the invention”as used herein unless otherwise specified, means a compound offormula(I) or (Ic) or a pharmaceutically acceptable salts or solventsthereof.

DETAILED DESCRIPTION OF THE INVENTION

Non-limiting examples of the above compounds according to the firstaspect will now be disclosed.

The compounds of the invention may exist in a continuum of solid statesranging from fully amorphous to fully crystalline. Compounds of theinvention may also exist in both unsolvated and solvated forms. The term“solvate” is used herein to describe a molecular complex comprising thecompound of the invention and a stoichiometric amount of one or morepharmaceutically acceptable solvent molecules. The term “hydrate” isemployed when said solvent is water. A pharmaceutically acceptable acidaddition salt may be readily prepared by using a desired acid asappropriate. Typically a pharmaceutically acceptable acid addition saltcan be formed by reaction of a compound of formula (I) or (Ic) with asuitable inorganic or organic acid (such as hydrobromic, hydrochloric,formic, sulfuric, nitric, phosphoric, succinic, maleic, acetic, fumaric,citric, tartaric, benzoic, p-toluenesulfonic, methanesulfonic ornaphthalenesulfonic acid), optionally in a suitable solvent such as anorganic solvent, to give the salt which is usually isolated for exampleby crystallisation and filtration. Thus, a pharmaceutically acceptableacid addition salt of a compound of formula (I) can be for example ahydrobromide, hydrochloride, formate, sulfate, nitrate, phosphate,succinate, maleate, acetate, fumarate, citrate, tartrate, benzoate,p-toluenesulfonate, methanesulfonate or naphthalenesulfonate salt.

Other non-pharmaceutically acceptable salts, e.g. oxalates ortrifluoroacetates, may be used, for example in the isolation ofcompounds of the invention, and are included within the scope of thisinvention. The invention includes within its scope all possiblestoichiometric and non-stoichiometric forms of the salts of thecompounds of formula (I) or (Ic) and is not limited to thosespecifically mentioned.

Compounds of the present invention can form addition salts, reaction ofthe amino substituent of formula (I) or (Ic) with a suitable acid.Pharmaceutically acceptable salts of the compounds of formula (I) or(Ic) include the acid salts addition of them.

It has now been found that a compound of the formula (I) or (Ic) or apharmaceutically acceptable salt and solvate thereof is particularuseful for the treatment of diseases, disorders or conditions caused bybacteria.

Examples of such diseases or disorders are mentioned above. Thecompounds of the invention show a particular surprising high activityagainst the bacteria selected from

-   -   Staphylococcus aureus    -   Streptococcus pyogenes, and    -   Streptococcus pneumoniae.

The activity is also high against strains that are resistant topenicillin-type antibiotics, such as methicillin, and even vancomycin.The compounds are effective in combating the bacteria at surprisinglylow micro molar levels such as 25 μM or less measured as MIC values. MICvalues of about 1 μM have been obtained.

The compounds are bactericidal against Gram-positive bacteria includingStaphylococcus aureus strains ATCC 33591, ATTC 29213 RN 4220,ATCC-BAA-44, ATCC-1720, ATCC-2094, ATCC-33591, ATCC-BAA-1680,ATCC-BAA-1681 and ATCC-700699.

For administration to human patients, the total daily dose of a compoundof the invention is typically in the range of 0.5 to 2 grams, but is notlimited to that range depending on the mode of administration. The totaldaily dose may be administered in single or divided doses, and may atthe physicians discretion, fall outside of the typical range.

Administration can be oral or parenteral or otherwise. In thepharmaceutical composition of the compounds of the invention excipientscan be used. The term “excipient” encompasses diluents, carriers andadjuvants.

If the compounds are administered in tablets such as for exampledisclosed in Tablets, Vol. 1, by H. Liberman and L. Lachman (MarcelDekker, New York, 1980).

The compounds of the invention may also be administered directly intothe blood stream, into muscle or into an internal organ. Suitable meansfor parenteral administration include intravenous, intraarterial,intraperitoneal, intrathecal, intraventricular, intraureathral,intrasternal, intracranial, intramuscular and subcutaneous. Suitabledevices for parenteral administration include needle injectors, needlefree injectors and infusion techniques.

The compounds may also be administered topically to the skin or mucosa,that is, dermally or transdermal. According to the invention it has beenfound that the compounds of formula (I) or (Ic) are especially useful insuch topical applications where they can combat methicillin resistantStaphylococcus aureus strains.

The compounds of the invention may also be administered directly to theeye or ear, typically in the form of drops of micronized suspension orsolution in isotonic, pH-adjusted, sterile saline.

The compounds can also be inhaled to treat infection of the respiratorytract. Typical inhalers and inhalation formulations can be used. Theformula (I) or (Ic) provides general definitions of the compoundsaccording to the invention.

The formula (I) or (Ic) provides general definitions of the compoundsaccording to the invention. Preferred substituents or ranges of theradicals given in the formula (I) or (Ic) are illustrated in thefollowing:

L₁ preferably represents —CO—, C₁-C₃-alkandiyl, —C₁-C₂-alkyl-CO— or—CO—C₁-C₂-alkyl-.

L₂ preferably represents —CO—, C₁-C₃-alkandiyl, —C₁-C₂-alkyl-CO— or—CO—C₁-C₂-alkyl-.

L₃ preferably represents —CO—, C₁-C₃-alkandiyl, —C₁-C₂-alkyl-CO— or—CO—C₁-C₂-alkyl-.

R₁ preferably represents hydrogen, C₁-C₂₀-alkyl-CO—, C₂-C₂₀-alkenyl-CO—,C₁-C₂₀-alkyl-NH—CO—, (C₁-C₂₀-alkyl)₂-N—CO—, arylcarbonyl having 6 or 10carbon atoms in the aryl moiety, C₃-C₇-cycloalkylcarbonyl orheterocyclylcarbonyl having 1 to 3 hetero atoms selected from N, O and Sin the 3 to 6 membered ring.

R₂ preferably represents optionally substituted C₁-C₁₂-alkyl,phenyl-C₁-C₄-alkyl, biphenyl-C₁-C₄-alkyl or naphthyl-C₁-C₄-alkyl.

R₃ preferably represents hydrogen or preferably represents optionallysubstituted C₁-C₁₂-alkyl, phenyl-C₁-C₄-alkyl, biphenyl-C₁-C₄-alkyl ornaphthyl-C₁-C₄-alkyl.

R₄ preferably represents optionally substituted C₁-C₁₂-alkandiyl,C₂-C₁₂-alkendiyl, C₂-C₁₂-alkyndiyl, C₃-C₇-cycloalkyldiyl,—C₁-C₆-alkyl-C₃-C₇-cycloalkyl-,—C₁-C₆-alkyl-C₃-C₇-cycloalkyl-C₁-C₆-alkyl-, —C₁-C₆-alkyl-phenyl- or—C₁-C₆-alkyl-naphtyl-.

R₅ preferably represents hydrogen or preferably represents optionallysubstituted C₁-C₁₂-alkyl, phenyl-C₁-C₄-alkyl, biphenyl-C₁-C₄-alkyl ornaphtyl-C₁-C₄-alkyl.

R₆ preferably represents hydrogen or preferably represents optionallysubstituted C₁-C₁₂-alkyl, phenyl-C₁-C₄-alkyl, biphenyl-C₁-C₄-alkyl ornaphtyl-C₁-C₄-alkyl.

-   n preferably is 0, 1, 2 or 3;-   m preferably is 0 or 1.-   Q preferably is —NH₂, —NH—C(NH)—NH₂ or    —NH—C(N—C₁-C₂-alkyl)-NH—C₁-C₂-alkyl.-   X preferably is NH or O;-   Z₁ preferably is —CH₂—;-   Z₂ preferably is a direct bond, C₁-C₃-alkandiyl, cyclohexyldiyl or    phenyldiyl.-   L₁ more preferably represents —CO—, —CH₂—, —CH₂—CH₂—, —CH₂—CO— or    —CO—CH₂—.-   L₂ more preferably represents —CO—, —CH₂—, —CH₂—CH₂—, —CH₂—CO— or    —CO—CH₂—.-   L₃ more preferably represents —CO—, —CH₂—, —CH₂—CH₂—, —CH₂—CO— or    —CO—CH₂—.-   R₁ more preferably represents hydrogen, C₁-C₁₆-alkyl-CO—,    C₂-C₁₆-alkenyl-CO—, C₁-C₁₆-alkyl-NH—CO—, (C₁-C₁₆-alkyl)₂-N—CO—;    phenylcarbonyl or heterocyclylcarbonyl having 1 to 2 hetero atoms    selected from N, O and S in the 3 to 6 membered ring.-   R₂ more preferably represents optionally halogen or C₁-C₄-alkyl    substituted C₁-C₁₂-alkyl, phenyl-C₁-C₂-alklyl, biphenyl-C₁-C₂-alklyl    or naphthyl-C₁-C₂-alklyl.-   R₃ more preferably represents hydrogen or more preferably represents    optionally halogen or C₁-C₄-alkyl substituted C₁-C₁₂-alkyl,    phenyl-C₁-C₂-alklyl, biphenyl-C₁-C₂-alklyl or naphthyl-C₁-C₂-alklyl.-   R₄ more preferably represents C₂-C₆-alkandiyl, C₂-C₆-alkendiyl,    C₂-C₆-alkyndiyl, C₃-C₇-cycloalkyldiyl,    —C₁-C₆-alkyl-C₃-C₇-cycloalkyl-,    —C₁-C₆-alkyl-C₃-C₇-cycloalkyl-C₁-C₆-alkyl-, —C(COOH)—C₁-C₆-alkyl-,    —C(CONH₂)—C₃H₆— or —C₁-C₆-alklyl-phenyl-.-   R₅ more preferably represents hydrogen or more preferably represents    optionally halogen or C₁-C₄-alkyl substituted C₁-C₁₂-alkyl,    phenyl-C₁-C₂-alklyl, biphenyl-C₁-C₂-alklyl or naphthyl-C₁-C₂-alklyl.-   R₆ more preferably represents hydrogen or more preferably represents    optionally halogen or C₁-C₄-alkyl substituted C₁-C₁₂-alkyl,    phenyl-C₁-C₂-alklyl, biphenyl-C₁-C₂-alklyl or naphthyl-C₁-C₂-alklyl.-   n more preferably is 0, 1, 2 or 3;-   m more preferably is 0 or 1.-   Q more preferably is —NH₂, —NH—C(NH)—NH₂ or —NH—C(N—CH₃)—NH—CH₃.-   X more preferably is NH or O.-   Z₁ more preferably is —CH₂—.-   Z₂ more preferably is a direct bond, —CH₂—, cyclohexyldiyl or    phenyldiyl;-   L₁ most preferably represents —CO— or —CH₂—.-   L₂ most preferably represents —CO— or —CH₂—.-   L₃ most preferably represents —CO— or —CH₂—.-   R₁ most preferably represents hydrogen, methylcarbonyl,    ethylcarbonyl, nonylcarbonyl or heterocyclylcarbonyl having 1 to 2    hetero atoms selected from N and O in the 3 to 6 membered ring;-   R₂ most preferably represents optionally halogen or C₁-C₄-alkyl    substituted benzyl, biphenylmethyl or naphtylmethyl.-   R₃ most preferably represents hydrogen or represents optionally    halogen or C₁-C₄-alkyl substituted benzyl, biphenylmethyl or    naphthylylmethyl.

R₄ most preferably represents propandiyl, butandiyl, pentandiyl,butendiyl, butyndiyl, cyclohexyldiyl, —C(COOH)—C₃H₆—, —C(CONH₂)—C₃H₆— or—CH₂—phenyl-.

-   R₅ most preferably represents hydrogen or represents optionally    halogen or C₁-C₄-alkyl substituted benzyl, biphenylmethyl or    naphthylmethyl.-   R₆ most preferably represents hydrogen or represents optionally    halogen or C₁-C₄-alkyl substituted methyl, benzyl, biphenylmethyl or    naphthylmethyl.-   n most preferably is 0, 1 or 2.-   m most preferably is 0 or 1.-   Q most preferably is —NH₂, —NH—C(NH)—NH₂ or —NH—C(N—CH₃)—NH—CH₃.-   X most preferably is NH or O.-   Z₁ most preferably is —CH₂—.-   Z₂ most preferably is a direct bond, —CH₂— or phenyldiyl.

The formula (Ia) provides general definitions of some selected compoundsaccording to the invention. Preferred substituents or ranges of theradicals given in the formula (Ia) are illustrated in the following:

-   R¹ preferably represents hydrogen, C₁-C₂₀-alkyl-CO—,    C₂-C₂₀-alkenyl-CO—, C₁-C₂₀-alkyl-NH—CO—, or (C₁-C₂₀-alkyl)₂-N—CO—.-   R² preferably represents optionally substituted C₁-C₁₂-alkyl,    phenyl-C₁-C₄-alkyl, biphenyl-C₁-C₄-alkyl or naphthyl-C₁-C₄-alkyl;-   R³ preferably represents optionally substituted C₁-C₁₂-alkyl,    phenyl-C₁-C₄-alkyl, biphenyl-C₁-C₄-alkyl or naphthyl-C₁-C₄-alkyl;-   R⁴ preferably represents optionally substituted C₁-C₁₂-alkandiyl,    C₂-C₁₂-alkendiyl, C₂-C₁₂-alkyndiyl, C₃-C₇-cycloalkyldiyl,    C₁-C₆-alkyl-C₃-C₇-cycloalkyl,    C₁-C₆-alkyl-C₃-C₇-cycloalkyl-C₁-C₆-alkyl, C₁-C₆-alkyl-phenyl or    C₁-C₆-alkyl-naphthyl;-   n preferably is 1, 2 or 3; and-   m preferably is 1.-   R¹ more preferably represents hydrogen, C₁-C₁₆-alkyl-CO—,    C₂-C₁₆-alkenyl-CO—, C₁-C₁₆-alkyl-NH—CO—, or (C₁-C₁₆-alkyl)₂-N—CO—.-   R² more preferably represents optionally halogen substituted C₁-C₁₂    alkyl, phenyl-C₁-C₂-alklyl, biphenyl-C₁-C₂-alklyl or    naphthyl-C₁-C₂-alklyl;-   R³ more preferably represents optionally halogen substituted    C₁-C₁₂-alkyl, phenyl-C₁-C₂-alklyl, biphenyl-C₁-C₂-alklyl or    naphthyl-C₁-C₂-alklyl;-   R⁴ more preferably represents C₂-C₆-alkandiyl, C₂-C₆-alkendiyl,    C₂-C₆-alkyndiyl, C₃-C₇-cycloalkyldiyl, C₁-C₆-alkyl-C₃-C₇-cycloalkyl,    C₁-C₆-alkyl-C₃-C₇-cycloalkyl-C₁-C₆-alkyl, —C(COOH)—C₁-C₆-alkyl-,    —C(CONH₂)—C₃H₆— or C₁-C₆-alklyl-phenyl;-   n more preferably is 1, 2 or 3; and-   m more preferably is 1.-   R¹ most preferably represents hydrogen or methylcarbonyl, with    hydrogen being particularly being preferred;-   R² most preferably represents optionally halogen substituted benzyl,    biphenylmethyl or naphthylmethyl;-   R³ most preferably represents optionally halogen substituted benzyl,    biphenylmethyl or naphthylmethyl;-   R⁴ most preferably propandiyl, butandiyl, pentandiyl, butendiyl,    butyndiyl, cyclohexyl, —C(COOH)—C₃H₆—, —C(CONH₂)—C₃H₆— or    —CH₂-Phenyl;-   n most preferably is 2 or 3.

The process for making the compounds of formula (I′) is described now inmore detail.

In a first reaction step known and commercially available diamines ofthe formula (VIII′) are reacted with N,N′-Di-Boc-S-methylisothiourea inthe presence of a base. This reagent is commercially available fromSigma/Aldrich. Bases can be customary acid acceptors such as tertiaryamines, preferably N,N-disopropylethylamine. Suitable solvents includeinert organic solvents such as hydrocarbons, preferably methylenedichloride (dichloromethane).

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

When carrying out this process step the starting materials of formula(VIII′) and the reagent are generally each employed in approximatelyequal amount. It may be beneficial to use the diamine of formula (VIII′)in excess to the reagent.

Work up is done by customary separation methods, preferably flashchromatography and evaporation of the solvents.

In a second reaction step the obtained compounds of the formula (VI′)are reacted with a compound of the formula (VII′). Compounds of theformula (VII′) are known or can be prepared according to known methods.For instance one of such compounds is commercially available from MerckMillipore and GL Biochem China as “Fmoc-4-phenyl-Phe-OH”,“Fmoc-4-phenyl-L-Phe-OH” or “Fmoc-Bip-OH”.

The amide/peptide coupling reagent can be customary coupling reagentssuch as 2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate (HBTU). Other suitable coupling reagents includeN,N′-Dicyclohexylcarbodiimide (DCC), (N,N′-Diisopropylcarbodiimide(DIC),(1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium3-oxid hexafluorophosphate (HATU),2-(6-Chloro-1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminiumhexafluorophosphate (HCTU),benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate(PyBop), 6-Chloro-benzotriazole-1-yloxy-tris-pyrrolidinophosphoniumhexafluorophosphate (Pyclock) or Ethyl 2-Cyano-2-(hydroxyimino)acetate(Oxyma). Preferably these coupling reagents are used in the presence ofa base such as for instance a tertiary amine, preferablyN,N-Diisopropylamine.

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

When carrying out this process step the starting materials of formula(VI′) and the compound of formula (VII′) are generally each employed inapproximately equal amount. It may be beneficial to use the compound offormula (VII′) in small excess.

Work up is done by customary separation methods, preferably by washingsteps and an evaporation of the solvent. Dissolution and furtherpost-reaction with a base, such as 1,8-Diazabicyclo[5.4.0]undec-7-ene(DBU), at room temperature and flash chromatography is possible.

In a third reaction step the obtained compounds of the formula (IV′) arereacted with a compound of the formula (V′). Compounds of the formula(V′) are known or can be prepared according to known methods. Forinstance one of such compounds is commercially available from MerckMillipore or GL Biochem as “Fmoc-Arg(Pbf)-OH” or Fmoc-Arg(Boc)₂-OH.

The amide/peptide coupling reagent can be customary coupling reagentssuch as 2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate (HBTU). Other suitable coupling reagents includeN,N′-Dicyclohexylcarbodiimide (DCC), (N,N′-Diisopropylcarbodiimide(DIC),(1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium3-oxid hexafluorophosphate (HATU),2-(6-Chloro-1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminiumhexafluorophosphate (HCTU),benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate(PyBop), 6-Chloro-benzotriazole-1-yloxy-tris-pyrrolidinophosphoniumhexafluorophosphate (Pyclock) or Ethyl 2-Cyano-2-(hydroxyimino)acetate(Oxyma). Preferably these coupling reagents are used in the presence ofa base such as for instance a tertiary amine, preferablyN,N-Diisopropylamine.

Suitable solvents include inert organic solvents such asdimethylforamide.

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

When carrying out this process step the starting materials of formula(IV′) and the compound of formula (V′) are generally each employed inapproximately equal amount. It may be beneficial to use the compound offormula (V′) in excess.

Work up is done by customary separation methods, preferably by washingsteps and an evaporation of the solvent. Dissolution and further postreaction with a base, such as 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)or piperidine, at room temperature and flash chromatography is possible.

In a fourth reaction step the obtained compounds of the formula (II′)are reacted with a compound of the formula (III′). Compounds of theformula (III′) are known or can be prepared according to known methods.For instance one of such compounds is commercially available from MerckMillipore or GL Biochem as “Fmoc-4-phenyl-Phe-OH” or “Fmoc-Bip-OH”. Itcan also be bought from Creosalus Advanced ChemTech.

The amide/peptide coupling reagent can be customary coupling reagentssuch as 2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate (HBTU). Other suitable coupling reagents includeN,N′-Dicyclohexylcarbodiimide (DCC), (N,N′-Diisopropylcarbodiimide(DIC),(1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium3-oxid hexafluorophosphate (HATU),2-(6-Chloro-1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminiumhexafluorophosphate (HCTU),benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate(PyBop), 6-Chloro-benzotriazole-1-yloxy-tris-pyrrolidinophosphoniumhexafluorophosphate (Pyclock) or Ethyl 2-Cyano-2-(hydroxyimino)acetate(Oxyma). Preferably these coupling reagents are used in the presence ofa base such as for instance a tertiary amine, preferablyN,N-Diisopropylamine.

Suitable solvents include inert organic solvents such asdimethylformamide.

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

When carrying out this process step the starting materials of formula(IV′) and the compound of formula (V′) are generally each employed inapproximately equal amount. It may be beneficial to use the compound offormula (V′) in excess.

Work up is done by customary separation methods, preferably by washingsteps and an evaporation of the solvent. Dissolution and furtherpost-reaction with a base, such as diazabicycloundecene (DBU) orpiperidine, at room temperature and flash chromatography is possible.

The compounds of the formula (I′) can be obtained from their precursorsby reaction with a strong organic acid such as trifluoroacetic acid.Such organic acids must be able to remove the Pbf and Boo moieties.

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

Work up is done by customary separation methods, preferably byevaporation of the solvent, re-dissolution, chromatography and HPLC.

Other compounds disclosed herein also can be synthesized analogous tothe compounds of Formula (I′) or can be synthesized utilizing knownmethodologies disclosed in texts well known to those skilled in the artsuch as Amino acids, Peptides and Proteins in Organic Chemistry, Ed. A.B. Hughes, vol. 4.; Wiley-VCH, Germany, 2011.

EXAMPLES Materials and Methods

In the examples described below, unless otherwise indicated, alltemperatures in the following description are in degrees Celsius and allparts and percentages are by weight, unless indicated otherwise.Reagents useful for synthesizing compounds may be purchased fromcommercial suppliers, such as Sigma-Aldrich Pte Ltd (Singapore 117528,Singapore), Merck Millipore, GL Biochem China or Creosalus AdvancedChemtech and others, and used without further purification, unlessotherwise indicated, or obtained or prepared according to techniquesknown in the art.

HPLC was conducted on a Shimadzu Prominence system. Mass spectrometrywas conducted using a Shimadsu LC-MS system.

All the NMR experiments for ¹H (400.13 MHz) and ¹³C (100.61 MHz) nucleiwere performed on a Bruker Ultrashield 400+ NMR spectrometer. NMRspectra are reported in ppm with reference to an internaltetramethylsilane standard (0.00 ppm for ¹H and ¹³C) or solvent peak(s)of CD₃OD (3.31 and 49.0 ppm). When peak multiplicities are reported, thefollowing abbreviations are used: s=singlet, d=doublet, t=triplet,q=quartet, m=multiplet, br=broadened, dd=doublet of doublets, dt=doubletof triplets, bs=broadened singlet. Coupling constants, when given, arereported in hertz.

Example 1 Preparation of Compound 1a (Bip-Arg-Bip-agmantine)

Step 1:

1,4-Diaminobutane (0.5 mmol, 44 mg),N,N-di-(t-butoxycarbonyl)-S-methylisothiourea (0.4 mmol, 116 mg) andN,N-diisopropylethylamine (DIPEA; 1 mmol, 175 μL) were dissolved inanhydrous CH₂Cl₂ (6 mL). The mixture was stirred at 25° C., 16 h underN₂ atmosphere and the resulting guanylated amine was purified by flashchromatography using a CH₂Cl₂/methanol gradient and monitored using MS.The solvent was removed in vacuo to give a colourless oil (79 mg, 0.24mmol, 60%).

Step 2:

Fmoc-Bip-OH (0.264 mmol), HBTU (0.48 mmol), DIPEA (0.72 mmol) anddimethylformamide (DMF, 10 mL) were added to the oil and the mixture wasstirred at 25° C. for 1 h.

Step 3:

The contents were dissolved in ethyl acetate (30 mL) and washed withbrine (50 mL) thrice. The organic phase was removed in vacuum to give ayellow gel which was dissolved in CH₂Cl₂ mL).

Step 4:

DBU (0.36 mmol, 54 μL) was added to the mixture and stirred at 25° C.for 1 h. The intermediate was purified by flash chromatography using aCH₂Cl₂/methanol gradient monitored using MS. The solvent was removed invacuo to give a colourless oil (0.20 mmol, 83%).

Step 5:

Fmoc-Arg(Pbf)-OH (0.264 mmol), HBTU (0.48 mmol), DIPEA (0.72 mmol) anddimethylformamide (DMF, 10 mL) were added to the oil and the mixture wasstirred at 25° C. for 1 h.

Step 6:

Steps 3 and 4 were repeated for Fmoc removal.

Step 7:

Step 2 was repeated.

Step 8:

Steps 3 and 4 were repeated for Fmoc removal.

Step 9:

TFA:CH₂Cl₂ (1.5 mL, 95:5 v/v) was added toBip-Arg(Pbf)-Bip-agmatine(Boc)₂ and stirred for 1 h at room temperature.

Step 10:

Excess TFA:CH₂Cl₂ was blown off using a gentle N₂(g) stream to yield ayellow oil. The oil was re-dissolved in MeOH and purified by HPLC (waterand acetonitrile solvent), retention time ˜16.5 min, to give the targetproduct (Bip-Arg-Bip-agmatine; BRB-Ag; ETC-2016975) as a white powder(4.1 mg, 0.006 mmol, 6% overall yield).

The electrospray ionization-mass spectrum (ESI-MS) shows threecharacteristic peaks at 367.5 [M+2H]²⁺, 733.4 [M+H] and 755.4 [M+Na]⁺.

The mass spectrum is shown in FIG. 1 a.

NMR Spectral data: ¹H NMR (400 MHz, CD₃OD) δ 1.20-1.77 (8H, m),2.75-3.24 (10H, m), 4.07, 4.33, 4.49 (1H, m, α-Hs), 7.10-7.52 (18H, m,aromatics); ¹³C NMR (100 MHz, CD₃OD) δ 24.6, 25.6, 26.0, 28.9, 36.9,37.5, 38.3, 40.5, 40.7 (methylene Cs), 52.9, 54.0, 54.8 (α-Cs), 126.3(×2), 126.5 (×2), 126.6 (×2), 126.9, 127.1, 127.2 (×2), 128.4 (×2),128.5 (×2), 129.5 (×2), 129.7 (×2), 132.9, 135.8, 139.6, 140.3, 140.4,140.6 (aromatics), 157.2, 157.3 (guanidinium), 168.3, 171.4, 171.9(C═O).

The ¹H and ¹³C NMR spectra are shown in FIGS. 1b and 1c respectively.

Example 1b Proposed Scheme for Solid-Phase Synthesis (24 step)

1. Anchor Fmoc-Bip-OH (5.0 mmol, 5 eq.) to 2-chlorotrityl chloride resin(1.0 mmol scale) with DIPEA (5.0 mmol, 5 eq.) in CH₂Cl₂ (10 mL) for 60minutes.

2. Filter off excess solvent/reagents and wash resin with CH₂Cl₂ (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

3. Remove Fmoc using piperidine: DMF (20% v/v) with stirring andmicrowave (40 W, 65° C., 5 min).

4. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

5. Dissolve Fmoc-Arg(Pbf)-OH (5.0 mmol, 5 eq.), HBTU (5.0 mmol, 5 eq.),DIPEA (5.0 mmol, 5 eq.) in DMF (10 mL) and allow this mixture to reactwith the resin and microwave (40 W, 65° C., 10 min).

6. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

7. Repeat step 3.

8. Repeat step 4.

9. Dissolve Fmoc-Bip-OH (5.0 mmol, 5 eq.), HBTU (5.0 mmol, 5 eq.), DIPEA(5.0 mmol, 5 eq.) in DMF (10 mL) and allow this mixture to react withthe resin and microwave (40 W, 65° C., 10 min).

10. Repeat step 4.

11. Repeat step 3.

12. Repeat step 4.

13. Dissolve Boc₂O (Boc-anhydride; 5.0 mmol, 5 eq.) and DIPEA (5.0 mmol,5 eq.) in DMF (10 mL) and allow this mixture to react with the resin andmicrowave (40 W, 65° C., 10 min).

14. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by CH₂Cl₂ (˜10 mL×2).

15. Add 10% acetic acid in CH₂Cl₂ (v/v) to the resin and stir (roomtemperature, 60 minutes)

16. Filter the mixture and neutralise the solution with NaHCO₃ until noeffervescence is seen.

17. Add CH₂Cl₂ and brine. The organic layer was concentrated in vacuo toyield crude Bip-Arg(Pbf)-Bip-OH as a yellow oil.

18. React 1,4-diaminobutane (2 mmol, 2 eq) with1,3-bis(tert-butoxycarbonyl)-2-methyl-2-thiopseudourea (obtainable fromSigma, 1 mmol) and DIPEA (6 mmol, 6 eq.) in CH₂Cl₂ for 60 minutes.

19. Purify the mixture with flash chromatography using hexane, EtOAc,CH₂Cl₂ and CH₃OH to obtain NH₂—(CH₂)₄-guanidine(Boc)₂ as a white solid.

20. Mix crude Bip-Arg(Pbf)-Bip-OH with NH₂—(CH₂)₄-guanidine(Boc)₂, EDC(1.2 mmol) and HOBt (1.2 mmol) in DMF (5 mL) and allow this mixture toreact overnight at room temperature.

21. The reaction mixture was extracted using ethyl acetate/brine and theorganic layer was concentrated in vacuo to yield a yellow oil.

22. Remove the Boc and Pbf with TFA and two drops of water usingmicrowave (40 W, 65° C., 10 min).

23. Excess TFA was blown off with a N₂ gas stream (˜20 min for 1 mL) toyield the crude target as yellow oil.

24. Purify the yellow oil with C₁₈ Reverse Phase HPLC.

Example 2 Biological Activity Measurement

The compounds of the working examples have been tested for biologicalactivity in the following assay:

Using a sterile loop, 3 to 5 isolated colonies of bacteria of the samemorphological appearance are selected from the overnight agar plate. Thecolonies are transferred into a conical flask containing 5 mL of liquidmedium (i.e. Mueller-Hinton broth). The broth is incubated at 37° C. ina shaker at 220 rpm until it reaches a turbidity that is equal to theturbidity of a McFarland Standard 0.5 (correspond to 1×108 cfu/mL). Thisculture growth step will require 1-2 hours depending on the bacteriatested.

During this pause period, an antibacterial dilution is prepared.Therefore an antibacterial stock solution is diluted in Mueller-Hintonbroth. The concentration of DMSO is kept at 5%. 100 μL of theantibacterial solution are dispensed into the first well of a row. 50 μLof medium containing 0.5% of DMSO are dispensed to the rest of thewells. A 2-fold serial dilution is achieved by transferring 50 μL fromthe first well (containing the highest concentration of antibacterial)into the second well, and continuing like this until the 10th well inthe row. The final 50 μL are discarded so that every well has 50 μL ofeach antibacterial dilution.

The 11th well was used as the growth control well (medium with bacterialinoculums, no antibacterial) while the 12th well was the sterilitycontrol well (medium only). Table 1 illustrates a typical sample layout.

The bacterial suspension prepared above is mixed thoroughly, and dilutedby a factor of 1:100 in the sterile medium. Each well and the growthcontrol well is inoculated with 50 μL of the bacterial suspension. Thisresulted in the final desired inoculums of 5×10⁵ cfu/mL in each well. Tothe sterility control well 50 μL of sterile medium are added in place ofthe bacterial suspension. 10 μL aliquot from the growth control well isremoved immediately after inoculating the plate and pipetted it into asterile Eppendorf tube holding 990 μL of sterile broth. It is mixed wellby vortexing. This suspension is further diluted (1:10) by pipetting 100μL into 900 μL of sterile broth and mixing it well. 100 μL of each ofthe two dilutions are plated onto two different antibacterial-free agarplates. A sterile cell spreader is used to spread the liquid. Then theplate is sealed with a transparent adhesive film.

The microtiter plate and agar plates are incubated at 37° C. for 16-20hours or until satisfactory growth is obtained. The colonies on the agarplate are counted the next day to verify that the right number of cfuwas inoculated. The plate is agitated in the SpectraMaxspectrophotometer for 90 s and the OD₆₀₀ for all the wells in the plateis recorded.

TABLE 1 Typical plate layout for the setup of a 96-well plate for thecell-based assay. Conc. (μg/mL) 1 2 3 4 5 6 7 8 9 10 11 12 A Linezolid125.00 62.50 31.25 15.63 7.81 3.91 1.95 0.98 0.49 0.24 GC SC B Linezolid125.00 62.50 31.25 15.63 7.81 3.91 1.95 0.98 0.49 0.24 GC SC C GC SC DGC SC E GC SC F G H GC SC GC: Growth control SC: Sterility control

The compound of example 1 (compound 1a) showed an MIC value of 3.125 μMvs. MRSA (ATCC 33591), S. aureus (RN 4220) and S. aureus (ATCC 29123)and 6.25 μM vs. Strep. pneumoniae (ATCC 49619) and Strep. pyogenes (ARC838). In the S. aureus tests the compound had a lower MIC value thancommercially available antibacterial compounds Linezolid and Daptomycin.In the Strep. tests it showed at least improvement over Daptomycin.

The compound also showed activity on E. faecalis.

FIG. 2 shows the bactericidal activity vs. S. aureus (ATCC 29213) at itsrespective MIC (compound of Example 1a on the left, Linezolid on theright) after dilution of the antibacterial. The picture on the leftshows that upon treatment with the compound of Example 1 at its MIC, thebacteria remains dead even after the antibacterial was diluted,suggesting that it possessed a bactericidal mode of action. The pictureon the right shows that upon treatment with Linezolid at its MIC, afterthe drug was diluted, the bacteria was able to re-grow, suggesting thatLinezolid is bacteriostatic.

Example 3 Synthesized Compounds of Formula (Ia)

According to the processes of the invention or known methods thefollowing other compounds of the formula (Ia) have been synthesized andtheir MIC value vs. MRSA (ATCC 33591) and S. aureus (ATCC 29213)determined:

(Ia)

MIC (μM) MIC (μM) No. R¹ R² R³ R⁴ m n (ATCC 33591) (ATCC 29213) 1a H BipBip —C₄H₈— 1 2 3.125 3.125 2a H Bip Bip —C₄H₈— 1 3 6.25 not determined3a H Bip Bip —C₅H₁₀— 1 2 6.25 12.5 4a H Bip Bip —C₃H₆— 1 2 50 50 5a HBip Bip —CH₂—CH═CH—CH₂— (trans) 1 2 100 12.5 6a H Bip Bip —CH₂—C≡C—CH₂—1 2 6.25 6.25 7a H Bip Bip —CH₂—C₆H₄— 0 2 6.25 6.25 8a H Naph Bip —C₄H₈—1 2 12.5 12.5 9a CH₃—CO— Bip Bip —C₄H₈— 1 2 12.5 6.25 10a H Bip Bip

1 2 25 25 11a H Bip Bip

1 2 12.5 12.5

FIGS. 3a to 3j show the mass spectra for the compounds 2a to 11a.

Example 4 Preparation of Compound (A)

The compound of the formula (A) has been prepared according to thefollowing process.

In a first reaction step known and commercially available1,4-diaminobutane was reacted with N,N′-Di-Boc-S-methylisothiourea inthe presence of a base. This reagent is commercially available fromSigma/Aldrich. Bases can be customary acid acceptors such as tertiaryamines, preferably N,N-disopropylethylamine. Suitable solvents includeinert organic solvents such as hydrocarbons, preferably methylenedichloride (dichloromethane).

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

When carrying out this process step the starting materials and thereagents are generally each employed in approximately equal amount. Itmay be beneficial to use the diamine in excess to the reagent.

Work up is done by customary separation methods, preferably flashchromatography and evaporation of the solvents.

In a second reaction step the obtained compounds of the formula:

were reacted with the compound of the formula:

which can be prepared according to known methods. For instance one ofsuch compounds is commercially available from Merck Millipore, GLBiochem China or Creosalus Advanced Chemtech as“Fmoc-4-phenyl-D-Phe-OH”, “Fmoc-4-phenyl-D-Phe-OH” or “Fmoc-D-Bip-OH”.

The amide/peptide coupling reagent can be customary coupling reagentssuch as 2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate (HBTU). Other suitable coupling reagents includeN,N′-Dicyclohexylcarbodiimide (DCC), (N,N′-Diisopropylcarbodiimide(DIC),(1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium3-oxid hexafluorophosphate (HATU),2-(6-Chloro-1H-benzotriazole-1-yl)-1,1,3₁3-tetramethylaminiumhexafluorophosphate (HCTU),benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate(PyBop), 6-Chloro-benzotriazole-1-yloxy-tris-pyrrolidinophosphoniumhexafluorophosphate (Pyclock) or Ethyl 2-Cyano-2-(hydroxyimino)acetate(Oxyma). Preferably these coupling reagents are used in the presence ofa base such as for instance a tertiary amine, preferablyN,N-Diisopropylamine.

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

When carrying out this process step the starting materials are generallyeach employed in approximately equal amount. It may be beneficial to usethe compound Fmoc-4-phenyl-Phe-OH in small excess.

Work up is done by customary separation methods, preferably by washingsteps and an evaporation of the solvent. Dissolution and furtherpost-reaction with a base, such as 1,8-Diazabicyclo[5.4.0]undec-7-ene(DBU), at room temperature and flash chromatography is possible.

In a third reaction step the obtained compound of the formula:

was reacted with a compound of one of the formulae:

Such compounds are known or can be prepared according to known methods.For instance one of such compounds is commercially available from MerckMillipore, GL Biochem, or Creosalus Advanced Chemtech as“Fmoc-D-Arg(Pbf)-OH” or “Fmoc-D-Arg(Boc)₂-OH”.

The amide/peptide coupling reagent can be customary coupling reagentssuch as 2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate (HBTU). Other suitable coupling reagents includeN,N′-Dicyclohexylcarbodiimide (DCC), (N,N′-Diisopropylcarbodiimide(DIC),(1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium3-oxid hexafluorophosphate (HATU),2-(6-Chloro-1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminiumhexafluorophosphate (HCTU),benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate(PyBop), 6-Chloro-benzotriazole-1-yloxy-tris-pyrrolidinophosphoniumhexafluorophosphate (Pyclock) or Ethyl 2-Cyano-2-(hydroxyimino)acetate(Oxyma). Preferably these coupling reagents are used in the presence ofa base such as for instance a tertiary amine, preferablyN,N-Diisopropylamine.

Suitable solvents include inert organic solvents such asdimethylforamide.

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

When carrying out this process step the starting materials and thecompound of formula are generally each employed in approximately equalamount. It may be beneficial to use Fmoc-D-Arg(Pbf)-OH orFmoc-D-Arg(Boc)₂-OH in excess.

Work up is done by customary separation methods, preferably by washingsteps and an evaporation of the solvent. Dissolution and further postreaction with a base, such as 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU),at room temperature and flash chromatography is possible.

In a fourth reaction step the obtained compound of the formula

was reacted with a compound of the formula:

which is known or can be prepared according to known methods.

For instance one of such compounds is commercially available from MerckMillipore, GL Biochem China or Creosalus Advanced Chemtech as“Fmoc-4-phenyl-D-Phe-OH”, “Fmoc-4-phenyl-D-Phe-OH” or “Fmoc-D-Bip-OH”.

The amide/peptide coupling reagent can be customary coupling reagentssuch as 2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate (HBTU). Other suitable coupling reagents includeN,N′-Dicyclohexylcarbodiimide (DCC), (N,N″-Diisopropylcarbodiimide(DIC),(1-[Bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium3-oxid hexafluorophosphate (HATU),2-(6-Chloro-1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminiumhexafluorophosphate (HCTU),benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate(PyBop), 6-Chloro-benzotriazole-1-yloxy-tris-pyrrolidinophosphoniumhexafluorophosphate (Pyclock) or Ethyl 2-Cyano-2-(hydroxyimino)acetate(Oxyma). Preferably these coupling reagents are used in the presence ofa base such as for instance a tertiary amine, preferablyN,N-Diisopropylamine.

Suitable solvents include inert organic solvents such asdimethylformamide.

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

When carrying out this process step the reaction materials are generallyeach employed in approximately equal amount. It may be beneficial to usethe compound Fmoc-4-phenyl-D-Phe-OH in excess.

Work up is done by customary separation methods, preferably by washingsteps and an evaporation of the solvent. Dissolution and furtherpost-reaction with a base, such as diazabicycloundecene (DBU), at roomtemperature and flash chromatography is possible.

Finally a precursor of the compound is obtained of the formula:

The compound of the formula (A) was obtained from the precursor byreaction with a strong organic acid such as trifluoroacetic acid. Suchorganic acids must be able to remove the Pbf and Boc moieties.

The reaction temperatures in this process step can be varied in arelatively wide range. In general the process is carried out attemperatures of 0 to 100° C., preferably 15 to 60° C., most preferablyat room temperature.

Work up is done by customary separation methods, preferably byevaporation of the solvent, re-dissolution, chromatography and HPLC.

Example 4a Additional Preparation Example: Synthetic Protocol for Makingof the Compound of Formula (A)

1. Anchor Fmoc-(D-Bip)-OH (1 mmol, 463.5 mg, 2 eq.) to 2-chlorotritylchloride resin (510 mg, 0.5 mmol scale) with DIPEA (1 mmol, 0.174 mL, 2eq.) in CH₂Cl₂ (10 mL) for 60 minutes.

2. Filter off excess solvent/reagents and wash resin with CH₂Cl₂ (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

3. Remove Fmoc using piperidine: DMF (20% v/v) with stirring for 30minutes at room temperature.

4. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

5. Dissolve Fmoc-(D-Arg)-OH (1 mmol, 648.7 mg, 2 eq.), HBTU (1 mmol, 380mg, 2 eq.), DIPEA (1 mmol, 0.174 mL, 2 eq.) in DMF (10 mL) and allowthis mixture to react with the resin for 60 minutes at room temperature.

6. Repeat step 4.

7. Repeat step 3.

8. Repeat step 4.

9. Dissolve Fmoc-(D-Bip)-OH (1 mmol, 463.5 mg, 2 eq.), HBTU (1 mmol, 380mg, 2 eq.), DIPEA (1 mmol, 0.174 mL, 2 eq.) in DMF (10 mL) and allowthis mixture to react with the resin for 60 minutes at room temperature.

10. Repeat step 4.

11. Repeat step 3.

12. Repeat step 4.

13. Dissolve Boc₂O (1 mmol, 218.3 mg, 2 eq.) and DIPEA (1 mmol, 0.174mL, 2 eq.) in DMF (10 mL) and allow this mixture to react with the resinfor 60 minutes at room temperature.

14. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by CH₂Cl₂ (˜10 mL×2).

15. Add 10% acetic acid in CH₂Cl₂ (v/v) to the resin and stir (roomtemperature, 60 minutes)

16. Filter the mixture and neutralise the solution with NaHCO3 until noeffervescence is seen.

17. Extract with CH₂Cl₂ and brine. The organic layer was concentrated invacuo to yield crude Boc-brb-OH as a yellow oil.

18. Mix crude Boc-brb-OH with NH₂—(CH₂)₄-guanidine(Boc)₂ (0.6 mmol, 199mg, 1.2 eq.), DIC (1.0 mmol, 0.157 mL) and HOAt(1-Hydroxy-7-azabenzotriazole obtained from GL Biochem, 1.0 mmol, 136mg) in DMF (5 mL) and allow this mixture to react overnight at roomtemperature.

19. The reaction mixture was extracted using EtOAc/brine and the organiclayer was concentrated in vacuo to yield a yellow oil.

20. Remove the Boc and Pbf with TFA and two drops of water at roomtemperature for 60 minutes.

21. Excess TFA was blown off with a N₂ gas stream (˜20 min for 1 mL) toyield the crude target as a yellow oil.

22. Purify the yellow oil with C18 Reverse Phase HPLC (18% initialacetonitrile concentration) to obtain the target as a white powder (86.6mg, 23% overall yield).

Example 4b Biological Activity of Compound (A)

According to the biological examples the MIC values (μM) of compound (A)for a panel of MRSA strains are:

ATCC-BAA-44 3.125 ATCC-1720 3.125 ATCC-2094 3.125 ATCC-33591 1.5625ATCC-BAA-1680 1.5625 ATCC-BAA-1681 3.125 ATCC-700699 3.125

Example 5 Synthetic Protocol for Making Compounds 10 and 11

For making the compounds 10 and 11 (see below) an intermediate targethas been obtained as shown by the synthetic route of FIG. 4.

This translated in the following synthetic protocol:

1. Stir Fmoc-Gly-OH (commercially available from Anaspec, Sigma/Aldrich,Sachem, Creosalus AdvancedChemTech, GL Biochem China, Novabiochem),DIPEA and Barbs resin (commercially available from Anaspec,Sigma/Aldrich, Bachem, Creosalus AdvancedChemTech, GL Biochem China,Novabiochem) in CH₂Cl₂ at room temperature for 1 h.

2. Drain solvent and excess reagents from resin.

3. Wash resin with CH₂Cl₂ followed by DMF.

4. Introduce 20% piperidine/DMF (v/v) to the resin and stir at roomtemperature for 30 minutes.

5. Repeat step 2.

6. Wash resin with DMF, CH₃OH followed by DMF.

7. Introduce Biphenyl-4-carboxaldehyde (purchased from Sigma/Aldrich),NaBH₃CN and 1% AcOH/DMF (v/v) to the resin and stir at room temperatureovernight.

8. Repeat steps 2 and 6.

9. Introduce either Fmoc-Arg(Pbf)-OH or Fmoc-D-Arg(Pbf)-OH, HATU, DIPEAand HOAt dissolved in DMF to the resin and stir at room temperature for1 h.

10. Repeat step 2.

11. Wash resin with DMF, CH₃OH followed by CH₂Cl₂.

12. Add 10% AcOH/CH₂Cl₂ (v/v) to the resin and stir at room temperaturefor 1 h.

13. Filter and collect the solvent containing the intermediate target(Fmoc-Arg-(B-peptoid)-OH), neutralise excess AcOH with NaHCO₃ andextract with CH₂Cl₂ before flash chromatography purification.

From this intermediate the compounds 10 and 11 have been synthesized:

Synthetic Protocol for Compound 10

1. Anchor Fmoc-Arg-(B-peptoid)-OH (1.0 mmol, 2 eq.) to 2-chlorotritylchloride resin (0.5 mmol scale) with DIPEA (1.0 mmol, 2 eq.) in CH₂Cl₂(10 mL) for 60 minutes.

2. Filter off excess solvent/reagents and wash resin with CH₂Cl₂ (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

3. Remove Fmoc using piperidine: DMF (20% v/v) with stirring for 30minutes at room temperature.

4. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

5. Dissolve Fmoc-Bip-OH (1.0 mmol, 2 eq.), HBTU (1.0 mmol, 2 eq.), DIPEA(1.0 mmol, 2 eq.) in DMF (10 mL) and allow this mixture to react withthe resin for 60 minutes at room temperature.

6. Repeat step 4.

7. Repeat step 3.

8. Repeat step 4.

9. Dissolve Boc₂O (1.0 mmol, 2 eq.) and DIPEA (1.0 mmol, 2 eq.) in DMF(10 mL) and allow this mixture to react with the resin for 60 minutes atroom temperature.

10. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by CH₂Cl₂ (˜10 mL×2).

11. Add 10% acetic acid in CH₂Cl₂ (v/v) to the resin and stir (roomtemperature, 60 minutes)

12. Filter the mixture and neutralise the solution with NaHCO₃ until noeffervescence is seen.

13. Extract with CH₂Cl₂ and brine. The organic layer was concentrated invacuo to yield crude Boc-Bip-Arg-(3-peptoid)-OH as a yellow oil.

14. React 1,4-diaminobutane (0.8 mmol, 2 eq) with1,3-bis(tert-butoxycarbonyl)-2-methyl-2-thiopseudourea (0.4 mmol) andDIPEA (2.4 mmol, 6 eq.) in CH₂Cl₂ (10 mL) for 60 minutes.

15. Purify the mixture with flash chromatography using hexane, EtOAc,CH₂Cl₂ and CH₃OH to obtain NH₂—(CH₂)₄-guanidine(Boc)₂ as a white solid.

16. Mix crude Boc-Bip-Arg-(B-peptoid)-OH withNH₂—(CH₂)₄-guanidine(Boc)₂, DIC (1.0 mmol) and HOAt (1.0 mmol) in DMF (5mL) and allow this mixture to react overnight at room temperature.

17. The reaction mixture was extracted using EtOAc/brine and the organiclayer was concentrated in vacuo to yield a yellow oil.

18. Remove the Boc and Pbf with TFA and two drops of water at roomtemperature for 60 minutes.

19. Excess TFA was blown off with a N₂ gas stream (˜20 min for 1 mL) toyield the crude target as a yellow oil.

20. Purify the yellow oil with C18 Reverse Phase HPLC (18% initialacetonitrile concentration) to obtain target as a colourless oil (24 mg,6.5%).

Synthetic Protocol for Compound 11

1. Anchor Fmoc-(D-Arg)-(B-peptoid)-OH (1.0 mmol, 2 eq.) to2-chlorotrityl chloride resin (0.5 mmol scale) with DIPEA (1.0 mmol, 2eq.) in CH₂Cl₂ (10 mL) for 60 minutes.

2. Filter off excess solvent/reagents and wash resin with CH₂Cl₂ (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

3. Remove Fmoc using piperidine:DMF (20% v/v) with stirring for 30minutes at room temperature.

4. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

5. Dissolve Fmoc-(D-Bip)-OH (1.0 mmol, 2 eq.), HBTU (1.0 mmol, 2 eq.),DIPEA (1.0 mmol, 2 eq.) in DMF (10 mL) and allow this mixture to reactwith the resin for 60 minutes at room temperature.

6. Repeat step 4.

7. Repeat step 3.

8. Repeat step 4.

9. Dissolve Boc₂O (1.0 mmol, 2 eq.) and DIPEA (1.0 mmol, 2 eq.) in DMF(10 mL) and allow this mixture to react with the resin for 60 minutes atroom temperature.

10. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by CH₂Cl₂ (˜10 mL×2).

11. Add 10% acetic acid in CH₂Cl₂ (v/v) to the resin and stir (roomtemperature, 60 minutes)

12. Filter the mixture and neutralise the solution with NaHCO₃ until noeffervescence is seen.

13. Extract with CH₂Cl₂ and brine. The organic layer was concentrated invacuo to yield crude Boc-bip-arg-(B-peptoid)-OH as a yellow oil.

14. React 1,4-diaminobutane (0.4 mmol, 2 eq) with1,3-bis(tert-butoxycarbonyl)-2-methyl-2-thiopseudourea (0.2 mmol) andDIPEA (1.2 mmol, 6 eq.) in CH₂Cl₂ (10 mL) for 60 minutes.

15. Purify the mixture with flash chromatography using hexane, EtOAc,CH₂Cl₂ and CH₃OH to obtain NH₂—(CH₂)₄-guanidine(Boc)₂ as a white solid.

16. React crude Boc-bip-arg-(B-peptoid)-OH withNH₂—(CH₂)4-guanidine(Boc)₂, DIC (1.2 mmol) and HOAt in DMF (5 mL) andallow this mixture to react overnight at room temperature.

17. The reaction mixture was extracted using EtOAc/brine and the organiclayer was concentrated in vacuo to yield a yellow oil.

18. Remove the Boc and Pbf with TFA and two drops of water at roomtemperature for 60 minutes.

19. Excess TFA was blown off with a N₂ gas stream (˜20 min for 1 mL) toyield the crude target as a yellow oil.

20. Purify the yellow oil with C18 Reverse Phase HPLC (18% initialacetonitrile concentration) to obtain target as a yellow oil (0.8 mg,0.4%).

Synthetic Protocol for Compounds 13 to 22

1. Anchor the first Fmoc-protected amino acid (1.0 mmol, 2 eq.) to2-chlorotrityl chloride resin (0.5 mmol scale) with diisopropylamine(DIPEA) (1.0 mmol, 2 eq.) in CH₂Cl₂ (10 mL) and stir for 60 minutes atroom temperature.

2. Filter off excess solvent/reagents and wash resin with CH₂Cl₂ (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

3. Remove Fmoc protecting group using piperidine:DMF (20% v/v) bystirring for 30 minutes at room temperature.

4. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

5. Dissolve the second Fmoc-protected amino acid (1.0 mmol, 2 eq.), HBTU(1.0 mmol, 2 eq.), DIPEA (1.0 mmol, 2 eq.) in DMF (10 mL) and allow thismixture to react with the resin for 60 minutes at room temperature.

6. Repeat step 4.

7. Repeat step 3.

8. Repeat step 4.

9. Dissolve the third Fmoc-protected amino acid (1.0 mmol, 2 eq.), HBTU(1.0 mmol, 2 eq.), DIPEA (1.0 mmol, 2 eq.) in DMF (10 mL) and allow thismixture to react with the resin for 60 minutes at room temperature.

10. Repeat step 4.

11. Repeat step 3.

12. Repeat step 4.

13. Dissolve Boc₂O (1.0 mmol, 2 eq.) and DIPEA (1.0 mmol, 2 eq.) in DMF(10 mL) and allow this mixture to cap the on-resin peptide for 60minutes at room temperature.

14. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by CH₂Cl₂ (˜10 mL×2).

15. Separate the Boc-protected peptide intermediate from the resin byadding 10% acetic acid in CH₂Cl₂ (v/v) to the resin and stir for 60minutes at room temperature.

16. Filter the mixture and neutralise the solution with NaHCO₃ until noeffervescence observed.

17. Extract with CH₂Cl₂ and brine. The organic layer was concentrated invacuo to yield crude Boc-protected peptide intermediate as an oilyliquid.

18. React 1,4-diaminobutane (0.4 mmol, 2 eq) with1,3-bis(tert-butoxycarbonyl)-2-methyl-2-thiopseudourea (0.2 mmol) andDIPEA (1.2 mmol, 6 eq.) in CH₂Cl₂ (10 mL) for 60 minutes at roomtemperature.

19. Purify the mixture with flash chromatography using hexane, ethylacetate, CH₂Cl₂ and CH₃OH to obtain NH₂—(CH₂)₄-guanidine(Boc)₂ as awhite solid.

20. Couple the crude Boc-protected peptide intermediate withNH₂—(CH₂)₄-guanidine(Boc)₂, DIC (1.2 mmol) and HOAt in DMF (5 mL)overnight at room temperature.

21. The reaction mixture was extracted using ethyl acetate/brine and theorganic layer was concentrated in vacuo to yield a yellow oil.

22. Remove the Boc and Pbf with TFA mixed with two drops of water for 60minutes at room temperature.

23. Excess TFA was blown off with a N₂ (g) stream (˜20 min for 1 mL) toyield the crude target as a yellow oil.

24. Purify the yellow oil by Reverse Phase HPLC to obtain target as ayellow oil (˜1 mg, ˜0.4% overall yield).

Synthetic Protocol Compounds 23 to 25

1. Anchor the first Fmoc-protected amino acid (1.0 mmol, 2 eq.) to2-chlorotrityl chloride resin (0.5 mmol scale) with diisopropylamine(DIPEA) (1.0 mmol, 2 eq.) in CH₂Cl₂ (10 mL) and stir for 60 minutes atroom temperature (room temperature).

2. Filter off excess solvent/reagents and wash resin with CH₂Cl₂ (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

3. Remove Fmoc protecting group using piperidine:DMF (20⁹6 v/v) bystirring for 30 minutes at room temperature.

4. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

5. Dissolve the second Fmoc-protected amino acid (1.0 mmol, 2 eq.), HBTU(1.0 mmol, 2 eq.), DIPEA (1.0 mmol, 2 eq.) in DMF (10 mL) and allow thismixture to react with the resin for 60 minutes at room temperature.

6. Repeat step 4.

7. Repeat step 3.

8. Repeat step 4.

9. Dissolve the third Fmoc-protected amino acid (1.0 mmol, 2 eq.), HBTU(1.0 mmol, 2 eq.), DIPEA (1.0 mmol, 2 eq.) in DMF (10 mL) and allow thismixture to react with the resin for 60 minutes at room temperature.

10. Repeat step 4.

11. Repeat step 3.

12. Repeat step 4.

13. Dissolve the appropriate organic acid, RCOOH (2.0 mmol, 2 eq.), DIC(2.0 mmol, 2 eq.) and HOAt in 1:1 CH₂Cl₂/DMF (10 mL) and allow thismixture to react with the on-resin peptide intermediate overnight atroom temperature.

14. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by CH₂Cl₂ (˜10 mL×2).

15. Separate the peptide intermediate from the resin by adding 106acetic acid in CH₂Cl₂ (v/v) to the resin and stir for 60 minutes at roomtemperature.

16. Filter the mixture and neutralise the solution with NaHCO3 until noeffervescence observed.

17. Extract with CH₂Cl₂ and brine. The organic layer was concentrated invacuo to yield crude Boc-protected peptide intermediate as an oilyliquid.

18. React 1,4-diaminobutane (0.4 mmol, 2 eq) with1,3-bis(tert-butoxycarbonyl)-2-methyl-2-thiopseudourea (0.2 mmol) andDIPEA (1.2 mmol, 6 eq.) in CH₂Cl₂ (10 mL) for 60 minutes at roomtemperature.

19. Purify the mixture with flash chromatography using hexane, ethylacetate, CH₂Cl₂ and CH₃OH to obtain NH₂—(CH₂)4-guanidine(Boc)₂ as awhite solid.

20. Couple the crude peptide intermediate withNH₂—(CH₂)₄-guanidine(Boc)₂, DIC (1.2 mmol) and HOAt in DMF (5 mL)overnight at room temperature.

21. The reaction mixture was extracted using ethyl acetate/brine and theorganic layer was concentrated in vacuo to yield a yellow oil.

22. Remove any acid-labile protecting group with TFA mixed with twodrops of water for 60 minutes at room temperature.

23. Excess TFA was blown off with a N₂ (g) stream (˜20 min for 1 mL) toyield the crude target as a yellow oil.

24. Purify the yellow oil by Reverse Phase HPLC to obtain target as aoff-white powder (˜1 mg, ˜0.4% overall yield).

Synthetic Protocol Compound 27

1. Anchor Fmoc-Bip-OH (1 mmol, 2 eq.) to 2-chlorotrityl chloride resin(0.5 mmol scale) with DIPEA (1 mmol, 2 eq.) in CH₂Cl₂ (10 mL) for 60minutes at room temperature.

2. Filter off excess solvent/reagents and wash resin with CH₂Cl₂ (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

3. Remove Fmoc using piperidine:DMF (20% v/v) with stirring for 30minutes at room temperature.

4. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

5. Dissolve Fmoc-Arg(Pbf)-OH (obtainable from Sigma, 1 mmol, 2 eq.),HBTU (1 mmol, 2 eq.), DIPEA (1 mmol, 2 eq.) in DMF (10 mL) and allowthis mixture to react with the resin for 60 minutes at room temperature.

6. Repeat step 4.

7. Repeat step 3.

8. Repeat step 4.

9. Dissolve Fmoc-Bip-OH (1 mmol, 2 eq.), HBTU (1 mmol, 2 eq.), DIPEA (1mmol, 2 eq.) in DMF (10 mL) and allow this mixture to react with theresin for 60 minutes at room temperature.

10. Repeat step 4.

11. Repeat step 3.

12. Repeat step 4.

13. Dissolve Boc₂O (1 mmol, 2 eq.) and DIPEA (1 mmol, 2 eq.) in DMF (10mL) and allow this mixture to react with the resin for 60 minutes atroom temperature.

14. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by CH₂Cl₂ (˜10 mL×2).

15. Add 10%, acetic acid in CH₂Cl₂ (v/v) to the resin and stir (roomtemperature, 60 minutes)

16. Filter the mixture and neutralise the solution with NaHCO₃ until noeffervescence is seen.

17. Extract with CH₂Cl₂ and brine. The organic layer was concentrated invacuo to yield crude Boc-BRB-OH as a yellow oil.

18. React crude Boc-BRB-OH with N,O-dimethylhydroxylamine hydrochloride(obtainable from Sigma-Aldrich, 0.6 mmol, 1.2 eq.), DIC (0.6 mmol, 1.2eq.) and DIPEA (0.6 mmol, 1.2 eq.) in DMF for 60 minutes at roomtemperature.

19. Extract with EtOAc/brine, concentrate in vacuo and purify by flashchromatography to obtain Boc-BRB-Weinreb.

20. Dissolve Boc-BRB-Weinreb in THF (˜10 mL) and cooled the solution to−78° C. Add LiAlH₄ (5 eq.) dropwise and allow the mixture to react for10 minutes Et₂O (˜15 mL) was then added and the mixture was allowed towarm to room temperature. Add citric acid (0.1M) dropwise and stir themixture for 30 minutes The mixture was then extracted with Et₂O/brineand concentrated in vacuo to yield Boc-BRB-H as a yellowish solid.

21. Mix Boc-BRB-H with NH₂—(CH₂)₄-guanidine(Boc)₂ (0.6 mmol, 1.2 eq.)and NaBH₃CN (3.0 mmol, 6 eq.) in 1% acetic acid/DMF (5 mL) and allowthis mixture to react overnight at room temperature.

22. Extract using ethyl acetate/brine and concentrate in vacuo to yielda yellow oil.

23. Remove any acid-labile protecting groups with TFA and two drops ofwater for 60 minutes at room temperature.

24. Excess TFA was blown off with a N₂ (g) stream to yield the crudetarget as a yellow oil.

25. Purify the yellow oil with C18 Reverse Phase HPLC (18% initial CH₃CNconcentration) to obtain target as a colourless gel (6.2 mg, 1.7%).

Synthetic Protocol Compound 28

1. React Fmoc-Bip-OH (0.6 mmol, 1.2 eq.) with NH₂—(CH₂)₄-guanidine(Boc)₂(0.5 mmol), DIC (0.6 mmol, 1.2 eq.) and HOAt in DMF (10 mL) for 3 h. atroom temperature.

2. Extract with ethyl acetate/brine and concentrate the organic layer invacuo.

3. Remove Fmoc using DBU (0.75 mmol, 1.5 eq.) in CH₂Cl₂ and allow themixture to react for 30 minutes at room temperature.

4. Evaporate the solvent and purify the residue using flashchromatography to yield NH₂-Bip-Ag(Boc)₂.

5. Anchor Fmoc-Arg-OH (1 mmol, 2 eq.) to 2-chlorotrityl chloride resin(0.5 mmol scale) with DIPEA (1 mmol, 2 eq.) in CH₂Cl₂ (10 mL) for 60minutes at room temperature.

6. Filter off excess solvent/reagents and wash resin with CH₂Cl₂ (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

7. Remove Fmoc using piperidine:DMF (20%, v/v) with stirring for 30minutes at room temperature.

8. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

9. Dissolve Fmoc-Bip-OH (1 mmol, 2 eq.), HBTU (1 mmol, 2 eq.), DIPEA (1mmol, 2 eq.) in DMF (10 mL) and allow this mixture to react with theresin for 60 minutes at room temperature.

10. Repeat step 8.

11. Repeat step 7.

12. Repeat step 8.

13. Dissolve Boc₂O (1 mmol, 2 eq.) and DIPEA (1 mmol, 2 eq.) in DMF (10mL) and allow this mixture to react with the resin for 60 minutes atroom temperature.

14. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by CH₂Cl₂ (˜10 mL×2).

15. Add 10% acetic acid in CH₂Cl₂ (v/v) to the resin and stir for 60minutes at room temperature.

16. Filter the mixture and neutralise the solution with NaHCO₃ until noeffervescence is seen.

17. Extract with CH₂Cl₂ and brine. The organic layer was concentrated invacuo to yield crude Boc-BR-OH as a yellow oil.

18. React crude Boc-BR-OH with N,O-dimethylhydroxylamine hydrochloride(0.6 mmol, 1.2 eq.), DIC (0.6 mmol, 1.2 eq.) and DIPEA (0.6 mmol, 1.2eq.) in DMF for 60 minutes at room temperature.

19. Extract with ethylacetate/brine, concentrate in vacuo and purify byflash chromatography to obtain Boc-BR-Weinreb.

20. Dissolve Boc-BR-Weinreb in THF (˜10 mL) and cool the solution to−78° C. Add LiAlH₄ (5 eq.) dropwise and allow the mixture to react for10 minutes Et₂O (˜15 mL) was then added and the mixture was allowed towarm to room temperature. Add citric acid (0.1M) dropwise and stir themixture for 30 minutes The mixture was then extracted with Et₂O/brineand concentrated in vacuo to yield Boc-BR-H as a yellow solid.

21. Mix Boc-BR-H with NH₂-Bip-(CH₂)₄-guanidine(Boc)₂ (0.6 mmol, 1.2 eq.)and NaBH₃CN (3.0 mmol, 6 eq.) in 1% acetic acid/DMF (5 mL) and allowthis mixture to react overnight at room temperature.

22. Extract using ethyl acetate/brine and concentrate in vacuo to yielda yellow oil.

23. Remove any acid-labile protecting group with TFA and two drops ofwater for 60 minutes at room temperature.

24. Excess TFA was blown off with a N₂ (g) stream to yield the crudetarget as a yellow oil.

25. Purify the yellow oil with C18 Reverse Phase HPLC (18% initial CH₃CNconcentration) to obtain target as a white powder (11.3 mg, 3.1%).

Synthetic Protocol Compound 29

1. React Fmoc-Bip-OH with N,O-dimethylhydroxylamine hydrochloride (0.6mmol, 1.2 eq.), DIC (0.6 mmol, 1.2 eq.) and diisopropylethylamine(DIPEA) (0.6 mmol, 1.2 eq.) in DMF for 60 minutes at room temperature.

2. Extract with ethyl acetate/brine, concentrate in vacuo and purifyusing flash chromatography to yield Fmoc-Bip-Weinreb.

3. Dissolve Fmoc-Bip-Weinreb in THF (˜10 mL) and cool the solution to−78° C. Add LiAlH₄ (5 eq.) dropwise and allow the mixture to react for10 minutes; add diethyl ether (˜15 mL) was and allow the mixture to warmto room temperature. Add citric acid (0.1M) dropwise and stir themixture for 30 minutes The mixture was then extracted with diethylether/brine and concentrated in vacuo to yield Fmoc-Bip-H as a yellowgel.

4. Anchor Fmoc-Bip-OH (1 mmol, 2 eq.) to 2-chlorotrityl chloride resin(0.5 mmol scale) with DIPEA (1 mmol, 2 eq.) in CH₂Cl₂ (10 mL) for 60minutes at room temperature.

5. Filter off excess solvent/reagents and wash resin with CH₂Cl₂ (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

6. Remove Fmoc using piperidine:DMF (20% v/v) with stirring for 30minutes at room temperature.

7. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by DMF (˜10 mL×2).

8. Dissolve Fmoc-Arg-OH (1 mmol, 2 eq.), HBTU (1 mmol, 2 eq.), DIPEA (1mmol, 2 eq.) in DMF (10 mL) and allow this mixture to react with theresin for 60 minutes at room temperature.

9. Repeat step 7.

10. Repeat step 6.

11. Repeat step 7.

12. Dissolve Fmoc-Bip-H (1.5 mmol, 3 eq.) and NaBH₃CN (3 mmol, 6 eq.) in1% acetic acid/DMF (10 mL) and allow this mixture to react with theresin overnight at room temperature.

13. Filter off excess solvent/reagents and wash resin with 1% aceticacid/DMF (˜10 mL), 5% DIPEA/DMF (˜10 mL), DMF (˜10 mL×2), CH₃OH (˜10mL×2) followed by DMF (. 10 mL×2) again.

14. Repeat step 6.

15. Repeat step 7.

16. Dissolve Boc₂O (1 mmol, 2 eq.) and DIPEA (1 mmol, 2 eq.) in DMF (10mL) and allow this mixture to react with the resin for 60 minutes atroom temperature.

17. Filter off excess solvent/reagents and wash resin with DMF (˜10mL×2), CH₃OH (˜10 mL×2) followed by CH₂Cl₂ (˜10 mL×2).

18. Add 10% acetic acid in CH₂Cl₂ (v/v) to the resin and stir for 60minutes at room temperature.

19. Filter the mixture and neutralise the solution with NaHCO₃ until noeffervescence is seen.

20. Extract with CH₂Cl₂ and brine. The organic layer was concentrated invacuo to yield crude Boc-BCH₂RB-OH as a yellow oil.

21. Mix Boc-BCH₂RB-OH with NH₂—(CH₂)₄-guanidine(Boc)₂ (0.6 mmol, 1.2eq.), DIC (0.6 mmol, 1.2 eq.) and HOAt in DMF (5 mL) and allow thismixture to react overnight at room temperature.

22. Extract using ethyl acetate/brine and concentrate in vacuo to yielda yellow oil.

23. Remove any acid-labile protecting groups with TFA and two drops ofwater for 60 minutes at room temperature.

24. Excess TFA was blown off with a N₂ (g) stream to yield the crudetarget as a yellow oil.

25. Purify the yellow oil with C18 Reverse Phase HPLC (18% initialacetonitrile concentration) to obtain target as a colourless gel (1.1mg, 0.3%).

According to the processes of the invention mentioned, the examples orknown methods the following other compounds have been synthesized andtheir MIC value vs. MRSA (ATCC 33591) in μM determined:

Structure:

Compound MIC

  Compound 1 1.56

  Compound 2 12.5

  Compound 3 25

  Compound 4 25

  Compound 5 25

  Compound 6 6.25

  Compound 7 6.25

  Compound 8 25

  Compound 9 50

  Compound 10 3.125

  Compound 11 12.5

  Compound 12 12.5

  Compound 13 6.25

  Compound 14 12.5

  Compound 15 12.5

  Compound 16 25

  Compound 17 6.25

  Compound 18 6.25

  Compound 19 6.25

  Compound 20 6.25

  Compound 21 6.25

  Compound 22 25

  Compound 23 12.5

  Compound 24 12.5

  Compound 25 12.5

  Compound 26 12.5

  Compound 27 6.25

  Compound 28 12.5

  Compound 29 3.125

The mass spectra of these compounds are shown in FIGS. 5a to 5 h.

FIG. 5i shows the NMR spectra of compound (A).

The NMR data of the other compounds is as follows:

-   Compound 2: ¹H NMR (400 MHz, CD₃OD) d 1.15-1.75 (8H, m), 2.85-3.30    (10H, m), 4.15 (1H, t), 4.30 (1H, t), 4.7(1H, t), 7.25-7.60 (18H, m,    aromatics).-   Compound 3: ¹H NMR (400 MHz, CD₃OD) d 0.95-1.5 (8H, m), 2.70-3.25    (10H, m), 4.10-4.20 (2H, m), 4.65 (1H, t), 7.25-7.65 (18H, m,    aromatics).-   Compound 4: ¹H NMR (400 MHz, CD₃OD) d 0.95-1.6 (8H, m), 2.7-3.30    (10H, m), 4.10-4.20 (2H, m), 5.60-5.70 (1H, m), 7.25-7.70 (18H, m,    aromatics).-   Compound 5: insufficient compound for NMR-   Compound 6: ¹H NMR (400 MHz, CD₃OD) d 1.20-1.90 (13H, m), 2.90-3.25    (5H, m), 3.35-3.50 (1H, s), 4.75 (1H, s), 5.15 ((1H, t), 5.45 (1H,    t), 5.65 (1H, t), 7.20-7.65 (18H, m, aromatics).-   Compound 7: ¹H NMR (400 MHz, CD₃OD) d 1.10-1.40 (5H, m), 1.55-2.05    (8H, m), 2.90-3.20 (6H, m), 3.55 (1H, m), 4.10 (1H, t), 4.40 (1H,    t), 4.55 (1H, t), 7.20-7.60 (18H, m, aromatics).-   Compound 8: ¹H NMR (400 MHz, CD₃OD) d 1.41-1.71 (8H, m), 1.55-2.05    (8H, m), 2.96-3.25 (10H, m), 4.13 (1H, t), 4.41 (1H, t), 4.52 (1H,    t), 7.18-7.59 (14H, m, aromatics).-   Compound 9: insufficient compound for NMR-   Compound 10: ¹H NMR (400 MHz, CD₃OD) d 1.05-1.85 (9H, m), 2.8-3.4    (9H, m), 4.15 (1H, t), 4.4 (1H, m), 4.5 (1H, m), 7.15-7.70 (13H, m,    aromatics).-   Compound 11: ¹H NMR (400 MHz, CD₃OD) d 1.40-2.05 (8H, m), 3.05-3.25    (8H, m), 3.70-3.95 (1H, dd), 4.20-4.60 (3H, m), 4.95 (1H, d), 5.05    (1H, t), 7.25-7.60 (18H, m, aromatics).-   Compound 12: insufficient compound for NMR-   Compound 13: ¹H NMR (400 MHz, CD₃OD) d 1.29-1.86 (9H, m), 2.89-3.16    (10H, m), 4.10 (1H, t), 4.42 (1H, t), 4.59 (1H, t), 7.23-7.50 (18H,    m, aromatics).-   Compound 14: ¹H NMR (400 MHz, CD₃OD) d 1.45-1.90 (8H, m), 2.65 (1H,    s), 2.90-3.20 (9H, m), 4.10 (1H, t), 4.45 (1H, t), 4.60 (1H, t),    7.20-7.60 (18H, m, aromatics).-   Compound 15: ¹H NMR (400 MHz, CD₃OD) d 1.40-1.85 (8H, m), 2.80 (6H,    s), 2.90-3.30 (10H, m), 4.20 (1H, t), 4.40 (1H, t), 4.60 (1H, t),    7.20-7.60 (18H, m, aromatics).-   Compound 16: ¹H NMR (400 MHz, CD₃OD) d 1.10 (1H, d), 1.40 (3H, m),    1.85 (2H, s), 2.90-3.60 (8H, m), 4.15 (1H, m), 4.55-4.70 (2H, m),    7.20-7.65 (18H, m, aromatics).-   Compound 17: ¹H NMR (400 MHz, CD₃OD) d 1.45 (4H, s), 2.8-3.2 (10H,    m), 4.1 (1H, t), 4.50 (1H, t), 4.65 (1H, t), 7.15-7.60 (22H, m,    aromatics).-   Compound 18: insufficient compound for NMR-   Compound 19: ¹H NMR (400 MHz, CD₃OD) d 1.25-1.85 (11H, m), 2.90-3.25    (9H, m), 4.15 (1H, t), 4.40 (1H, t), 4.60 (1H, t), 7.20-7.60 (18H,    m, aromatics).-   Compound 20: ¹H NMR (400 MHz, CD₃OD) d 1.35-1.54 (8H, m),    2.30-2.38(2H, m), 2.85-3.19 (10H, m), 4.08 (1H, t), 4.16 (1H, t),    4.59 (1H, t), 7.30-7.62 (18H, m, aromatics).-   Compound 21: ¹H NMR (400 MHz, CD₃OD) d 1.40-1.70 (6H, m), 2.90-3.30    (11H, m), 3.80-4.00 (2H, q), 4.15 (1H, d), 4.40 (1H, t), 4.65 (1H,    t), 7.25-7.65 (18H, m, aromatics).-   Compound 22: ¹H NMR (400 MHz, CD₃OD) d 1.09 (1H, m), 1.48-1.85 (8H,    m), 2.86-3.19 (9H, m), 4.07 (1H, t), 4.40 (1H, t), 4.60 (1H, t),    7.09-7.57 (13H, m, aromatics).-   Compound 23: ¹H NMR (400 MHz, CD₃OD) d 1.52-1.80 (8H, m), 1.92 (3H,    s), 2.65 (1H, s), 2.91-3.13 (9H, m), 4.32 (1H, t), 4.51-4.56 (2H,    m), 7.25-7.58 (18H, m, aromatics).-   Compound 24: ¹H NMR (400 MHz, CD₃OD) d 1.47-2.00 (8H, m), 2.21-2.23    (2H, t), 2.35-2.45 (2H, m), 2.65 (1H, s), 2.92-3.16 (8H, m), 4.17    (1H, m), 4.35 (1H, m), 4.57(2H, m), 7.25-7.59 (18H, m, aromatics).-   Compound 25: ¹H NMR (400 MHz, CD₃OD) d 0.85 (3H, t), 1.10-1.75 (23H,    m), 2.14-2.17 (2H, m), 2.89-2.99 (9H, m), 4.20 (1H, t), 4.61 (2H,    m), 7.28-7.59 (18H, m, aromatics).-   Compound 26: ¹H NMR (400 MHz, CD₃OD) d 1.09 (1H, d), 1.29-1.35 (16H,    m), 1.47 (3H, s), 1.62-1.90 (4H, m), 2.65 (3H, s), 2.99-3.20 (10H,    m), 4.12 (1H, s), 4.45 (1H, s), 4.61 (1H,$), 7.23-7.55 (16H, m,    aromatics).-   Compound 27: ¹H NMR (400 MHz, CD₃OD) d 1.60-1.77 (8H, m), 3.62 (4H,    s), 2.81-3.21 (11H, m), 7.32-7.64 (18H, m, aromatics).-   Compound 28: ¹H NMR (400 MHz, CD₃OD) d 1.30-1.52 (8H, m), 2.66 (1H,    s), 2.93-3.00 (6H, m), 3.08-3.24 (5H, m), 4.13-4.20 (2H, m), 4.26    (1H, s), 7.33-7.67 (18H, m, aromatics).-   Compound 29: ¹H NMR (400 MHz, CD₃OD) d 1.44-1.62 (8H, m), 2.56-2.60    (2H, m), 2.84-3.16 (13H, m), 3.38-3.49 (2H, m), 4.70 (1H, m),    7.22-7.59 (18H, m, aromatics).

It will be apparent that this and various other modifications andadaptations of the invention will be apparent to the person skilled inthe art after reading the foregoing disclosure without departing fromthe spirit and scope of the invention and it is intended that all suchmodifications and adaptations come within the scope of the appendedclaims.

1. A compound of the formula (I) or (Ic):

wherein L₁ represents —CO—, alkandiyl, -alkyl-CO— or —CO-alkyl-; L₂represents —CO—, alkandiyl, -alkyl-CO— or —CO-alkyl-; L₃ represents—CO—, alkandiyl, -alkyl-CO— or —CO-alkyl-; R₁ represents hydrogen, acyl,carbamoyl, alkylaminocarbonyl, dialkylaminocarbonyl, arylcarbonyl,cycloalkylarbonyl or heterocyclylcarbonyl; R₂ represents optionallysubstituted alkyl, aralkyl or heteroaralkyl; R₃ represents hydrogen, orrepresents optionally substituted alkyl, aralkyl or heteroaralkyl; R₄represents optionally substituted alkandiyl, alkendiyl, alkyndiyl,cycloalkyldiyl, alkylcycloalkyldiyl, alkylcycloalkylalkyldiyl, aryldiyl,alkylaryldiyl, alkylarylalkyldiyl; R₅ represents hydrogen, or representsoptionally substituted alkyl, aralkyl or heteroaralkyl; R₆ representshydrogen, or represents optionally substituted alkyl, aralkyl orheteroaralkyl; provided that at least two of the substituents R₂, R₃, R₅and R₆ are optionally substituted aralkyl or heteroaralkyl; n is 0, 1,2, 3 or 4; and m is 0 or 1; Q is —NH₂, —NH—C(NH)—NH₂ or—NH—C(N-alkyl)-NH-alkyl; X is NH, O or S; Z₁ is —CH₂—; Z₂ is a directbond, alkandiyl, cycloalkyldiyl or aryldiyl; or a salt and solvate ofsuch compound.
 2. A compound of formula (I) or (Ic) according to claim1, wherein L₁ represents —CO—, C₁-C₃-alkandiyl, —C₁-C₂-alkyl-CO— or—CO—C₁-C₂-alkyl-; L₂ represents —CO—, C₁-C₃-alkandiyl, —C₁-C₂-alkyl-CO—or —CO—C₁-C₂-alkyl-; L₃ represents —CO—, C₁-C₃-alkandiyl,—C₁-C₂-alkyl-CO— or —CO—C₁-C₂-alkyl-; R¹ represents hydrogen,C₁-C₂₀-alkyl-CO—, C₂-C₂₀-alkenyl-CO—, C₁-C₂₀-alkyl-NH—CO—,(C₁-C₂₀-alkyl)₂-N—CO—, arylcarbonyl having 6 or 10 carbon atoms in thearyl moiety, C₃-C₇-cycloalkylcarbonyl or heterocyclylcarbonyl having 1to 3 hetero atoms selected from N, O and S in the 3 to 6 membered ring;R² represents optionally substituted C₁-C₁₂-alkyl, phenyl-C₁-C₄-alkyl,biphenyl-C₁-C₄-alkyl or naphthyl-C₁-C₄-alkyl; R³ represents hydrogen orrepresents optionally substituted C₁-C₁₂-alkyl, phenyl-C₁-C₄-alkylbiphenyl-C₁-C₄-alkyl or naphthyl-C₁-C₄-alkyl; R⁴ represents optionallysubstituted C₁-C₁₂-alkandiyl, C₂-C₁₂-alkendiyl, C₂-C₁₂-alkyndiyl,C₃-C₇-cycloalkyldiyl, C₁-C₆-alkyl-C₃-C₇-cycloalkyl-,—C₁-C₆-alkyl-C₃-C₇-cycloalkyl-C₁-C₆-alkyl-, —C₁-C₆-alkyl-phenyl- or—C₁-C₆-alkyl-naphtyl-; R⁵ represents hydrogen or represents optionallysubstituted C₁-C₁₂-alkyl, phenyl-C₁-C₄-alkyl, biphenyl-C₁-C₄-alkyl ornaphtyl-C₁-C₄-alkyl; R⁶ represents hydrogen or represents optionallysubstituted C₁-C₁₂-alkyl, phenyl-C₁-C₄-alkyl, biphenyl-C₁-C₄-alkyl ornaphtyl-C₁-C₄-alkyl; n is 0, 1, 2 or 3; m is 0 or 1; Q is —NH₂,—NH—C(NH)—NH₂ or —NH—C(N—C₁-C₂-alkyl)-NH—C₁-C₂-alkyl; X is NH or O; Z₁is —CH₂—; Z₂ is a direct bond, C₁-C₃-alkandiyl, cyclohexyldiyl orphenyldiyl; or a pharmaceutically acceptable salt and solvate of suchcompound.
 3. A compound of formula (I) or (Ic) according to claim 1,wherein L₁ represents —CO—, —CH₂—, —CH₂—CH₂—, —CH₂—CO— or —CO—CH₂—; L₂represents —CO—, —CH₂—, —CH₂—CH₂—, —CH₂—CO— or —CO—CH₂—; L₃ represents—CO—, —CH₂—, —CH₂—CH₂—, —CH₂—CO— or —CO—CH₂—; R¹ represents hydrogen,C₁-C₁₆-alkyl-CO—, C₂-C₁₆-alkenyl-CO—, C₁-C₁₆-alkyl-NH—CO—,(C₁-C₁₆-alkyl)₂-N—CO—; phenylcarbonyl or heterocyclylcarbonyl having 1to 2 hetero atoms selected from N, O and S in the 3 to 6 membered ring;R² represents optionally halogen or C₁-C₄-alkyl substitutedC₁-C₁₂-alkyl, phenyl-C₁-C₂-alklyl, biphenyl-C₁-C₂-alklyl ornaphthyl-C₁-C₂-alklyl; R³ represents hydrogen or represents optionallyhalogen or C₁-C₄-alkyl substituted C₁-C₁₂-alkyl, phenyl-C₁-C₂-alklyl,biphenyl-C₁-C₂-alklyl or naphthyl-C₁-C₂-alklyl; R⁴ representsC₂-C₆-alkandiyl, C₂-C₆-alkendiyl, C₂-C₆-alkyndiyl, C₃-C₇-cycloalkyldiyl,—C₁-C₆-alkyl-C₃-C₇-cycloalkyl-,—C₁-C₆-alkyl-C₃-C₇-cycloalkyl-C₁-C₆-alkyl-, —C(COOH)—C₁-C₆-alkyl-,—C(CONH₂)—C₃H₆— or —C₁-C₆-alklyl-phenyl-; R⁵ represents hydrogen orrepresents optionally halogen or C₁-C₄-alkyl substituted C₁-C₁₂-alkyl,phenyl-C₁-C₂-alklyl, biphenyl-C₁-C₂-alklyl or naphthyl-C₁-C₂-alklyl; R⁶represents hydrogen or represents optionally halogen or C₁-C₄-alkylsubstituted C₁-C₁₂-alkyl, phenyl-C₁-C₂-alklyl, biphenyl-C₁-C₂-alklyl ornaphthyl-C₁-C₂-alklyl; n is 0, 1, 2 or 3; m is 0 or 1; Q is —NH₂,—NH—C(NH)—NH₂ or —NH—C(N—CH₃)—NH—CH₃; X is NH or O; Z₁ is —CH₂—; Z₂ is adirect bond, —CH₂—, cyclohexyldiyl or phenyldiyl.
 4. A compound offormula (I) or (Ic) according to claim 1, wherein L₁ represents —CO— or—CH₂—; L₂ represents —CO—, —CH₂— or —CH₂—CO—; L₃ represents —CO— or—CH₂—; R¹ represents hydrogen, methylcarbonyl, ethylcarbonyl,nonylcarbonyl or heterocyclylcarbonyl having 1 to 2 hetero atomsselected from N and O in the 3 to 6 membered ring; R² representsoptionally halogen or C₁-C₄-alkyl substituted benzyl, biphenylmethyl ornaphtylmethyl; R³ represents hydrogen or represents optionally halogenor C₁-C₄-alkyl substituted benzyl, biphenylmethyl or naphthylylmethyl;R⁴ represents propandiyl, butandiyl, pentandiyl, butendiyl, butyndiyl,cyclohexyldiyl, —C(COOH)—C₃H₆—, —C(CONH₂)—C₃H₆— or —CH₂-phenyl; R⁵represents hydrogen or represents optionally halogen or C₁-C₄-alkylsubstituted benzyl, biphenylmethyl or naphthylmethyl; R⁶ representshydrogen or represents optionally halogen or C₁-C₄-alkyl substitutedmethyl, benzyl, biphenylmethyl or naphthylmethyl; n is 0, 1, 2 or 3; mis 0 or 1; Q is —NH₂, —NH—C(NH)—NH₂ or —NH—C(N—CH₃)—NH—CH₃; X is NH orO; Z₁ is —CH₂—; Z₂ is a direct bond, —CH₂— or phenyldiyl.
 5. (canceled)6. (canceled)
 7. A process for making compounds of the formula (I′)

wherein R′₁ represents hydrogen, acyl, carbamoyl, alkylaminocarbonyl,dialkylaminocarbonyl, arylcarbonyl, cycloalkylarbonyl orheterocyclylcarbonyl; R′₂ represents optionally substituted alkyl,aralkyl or heteroaralkyl; R′₃ represents optionally substituted alkyl,aralkyl or heteroaralkyl; R′₄ represents optionally substitutedalkandiyl, alkendiyl, alkyndiyl, cycloalkyldiyl, alkylcycloalkyl,alkylcycloalkylalkyl or alkylaryl; n′ is 0, 1, 2, 3 or 4; and m′ is 0 or1; by reacting compounds of the formula (II′)

in which R′₃, R′₄, m and n have the meaning given above in the presenceof an amide/peptide coupling reagent with compounds of the formula

wherein R′₁ and R′₂ are defined as mentioned above, and deprotectionwith an acid. 8.-14. (canceled)
 15. A method of treating a bacterialinfection caused disease, disorder or condition in a subject in need ofsuch treatment, comprising administering to said subject a compound offormula (I) or (Ic) according to claim 1 or pharmaceutically acceptablesalts and solvates thereof or a pharmaceutical composition according toclaim
 6. 16. A pharmaceutical composition comprising a compound offormula (I) or (Ic) according to claim 1 or pharmaceutically acceptablesalts and solvates thereof and a pharmaceutical acceptable excipient.17. (canceled)
 18. The method of claim 15, wherein the bacterialinfection is caused by bacteria that have gained a resistance againstthe penicillin-type antibiotics or vancomycin.
 19. The method of claim15, wherein the bacterial infection is treated by topical use of thecompound.